# Aerial bombing of cities

The aerial bombing of cities is an optional element of strategic bombing, which became widespread in warfare during World War I. The bombing of cities grew to a vast scale in World War II and is still practiced today. The development of aerial bombardment marked an increased capacity of armed forces to deliver ordnance from the air against combatants, military bases, and factories, with a greatly reduced risk to its ground forces. The killing of civilians and non-combatants in bombed cities has variously been a deliberate goal of strategic bombing, or unavoidable collateral damage resulting from intent and technology. A number of multilateral efforts have been made to restrict the use of aerial bombardment so as to protect non-combatants and other civilians.

## Before World War I
### Kites

Incendiary kites were first used in warfare by the Chinese. During the Song dynasty the Fire Crow, a kite carrying incendiary powder, a fuse, and a burning stick of incense was developed as a weapon. Walter de Milemete's 1326 De nobilitatibus, sapientiis, et prudentiis regum treatise depicts a group of knights flying kites laden with a black-powder filled firebomb over the wall of city. In the 17th century, the forces of Thai king Phetracha tied gunpowder barrels to kites used for airborne assault.

### First Italian War of Independence

In 1849, Austrian forces besieging Venice during the First Italian War of Independence launched some 200 incendiary balloons, each carrying a 24- to 30-pound bomb that was to be dropped from the balloon with a time fuse over the besieged city. The balloons were launched from land and from the Austrian navy ship SMS Vulcano that acted as a balloon carrier, though the attack ended in failure as winds blew the balloons away, none reaching their intended target.

### Italian Invasion of Libya

The first ever air raid was conducted during the Italo-Turkish War by Italian forces against the Ottoman province of Libya on November 1, 1911. Giulio Gavotti dropped 1.5 kg of bombs on Ain Zara, a village 8 km west of the capital Tripoli.

### Balkan War

Adrianople (presently Edirne) was bombed by Bulgaria in 1912 in the First Balkan War. Historically, it was the first bombardment of a city from a heavier-than-air aircraft. In the morning of 29 October 1912 at 9:30 a.m. the plane Albatros F-3 took off from an airfield near the village of Mustafa Pasha – present day Svilengrad, Bulgaria. The pilot was captain Radul Mikov with spotter and bombardier Prodan Tarakchiev. The airfield was specially created to carry out the take off and landing. According to the report weather conditions were perfect. The flight lasted for 1 hour and 20 minutes and the altitude was 500m. During the flight the crew flew over the city of Edirne, discovered hidden Ottoman forces in the nearby villages and flew towards to city railroad station, near the village of Karaagach. The plane was equipped with two bombs, which were released at 10:00 am over the station. The crew landed successfully at the airfield with 4 holes on the hull. A number of journalists and military attachés attended the site.

### Mexican Revolution

In May 1914, during the revolution of 1910–17, General Venustiano Carranza, later president, ordered a biplane to bomb Neveria Hill adjacent to the downtown area of Mazatlán in order to take the city. The bomb landed not on target but in a city street and in the process killed four civilians, including a French diplomat, and wounded several others.

## World War I

The first civilian target to be bombed from the air was the Belgian city of Antwerp. This city, at that moment the National Redoubt of Belgium, was bombed during the night of 24–25 August 1914. Instead of targeting the surrounding fortresses, the Zeppelin LZ 25's intention was to bomb the clearly distinguishable historical centre of the city. The zeppelin dropped approximately ten bombs, killing ten people and injuring forty. The British Royal Naval Air Service (RNAS) undertook the first Entente strategic bombing missions on 22 September 1914 and 8 October, when it bombed the Zeppelin bases in Cologne and Düsseldorf. The aeroplanes carried twenty-pound bombs, and at least one airship was destroyed. On 19 January 1915 two German Zeppelins dropped 24 fifty-kilogram (110 lb) high-explosive bombs and ineffective three-kilogram incendiaries on the English towns of Great Yarmouth, Sheringham, King's Lynn, and the surrounding villages; in all, four people were killed, 16 injured, and monetary damage was estimated at £7,740.
London was bombed for the first time on 30 May 1915. In July 1916, the German government allowed directed raids against urban centers, sparking 23 airship raids in 1916 in which 125 tons of ordnance were dropped, killing 293 people and injuring 691. Gradually British air defenses improved and the Germans also introduced large bomber aircraft for bombing Britain. In 1917 and 1918 there were only eleven Zeppelin raids against England, and the final raid occurred on 5 August 1918, which resulted in the death of KK Peter Strasser, commander of the German Naval Airship Department. By the end of the war, 51 raids had been undertaken, in which 5,806 bombs were dropped, killing 557 people and injuring 1,358. In the course of the Zeppelin raids the Germans lost more than half their airships and 40% of their crew. It has been argued that the raids were effective far beyond material damage inflicted, in diverting and hampering wartime production, and diverting twelve squadrons and over 10,000 men to air defenses. The British developed an Independent Force of long-range bombers that could bomb Berlin, but the war ended before these raids began.
After the war, bombers' increasing sophistication led to the general belief that aerial bombing would both destroy cities and be impossible to stop; as Stanley Baldwin stated in a 1932 speech, "The bomber will always get through".

## Interwar period
### Iraqi revolt against the British

After World War I, there were protests in Iraq against continued British rule. Many Iraqis across a wide spectrum of opinion opposed the British Mandate for Iraq. The Iraqi revolt against the British began, with peaceful demonstrations in May 1920. Initial demands were rejected by the British administration, and fighting broke out in June 1920. This was suppressed, with many deaths, and at very high costs to the Empire. A policy of 'aerial policing', an invention of Winston Churchill's was brought in. This amounted to aerial bombing of rebelling tribesmen, followed up by pacification by ground troops. This continued up to the mid 1920s. The aerial campaign included Sir Arthur Harris, who commanded a Vickers Vernon squadron engaged in the bombing and strafing of revolting tribesmen. Harris once remarked that "the only thing the Arab understands is the heavy hand."

### Somaliland Campaign

Following the end of World War I, the British stepped up their efforts in their war against the Dervish movement, their sultan Diiriye Guure and emir, the so-called "Mad Mullah", whom they had been fighting for the control the area formerly known as British Somaliland. However, they had been unable to defeat the Dervish movement for nearly 25 years. In January 1920, the British launched a combined aerial and land attack against the Dhulbahante garesas, bombarding Taleeh, the capital of the revolt. The Somaliland Campaign has been described as one of the bloodiest and longest-running conflicts in the history of sub-Saharan Africa and the Somali forces are noted for concurrently repelling the invading British, Italian and Abyssinian forces for a period of 25 years.

### Tulsa race massacre

In the United States during the Tulsa race massacre of May 31 – June 1, 1921, private aircraft flown by white men dropped kerosene bombs on the Greenwood neighborhood.

### Cristero War

During the Cristero War in Mexico in 1929, Irish pilot and mercenary Patrick Murphy mistakenly dropped several improvised "suitcase bombs" on the border town of Naco, Arizona, while bombing government forces in the adjacent town of Naco, Sonora, for the Cristero revolutionaries. The bombing, which caused damage to many buildings and injured several bystanders on the American side of the international border, became the first aerial bombardment of the Continental United States by a foreign power in American history.

### Second Italo-Abyssinian War

The Italians used aircraft against the Ethiopian cities in the Second Italo-Abyssinian War. For example, in February 1936, the Italian invasion forces in the south prepared for a major thrust towards the city of Harar. On 22 March, the Regia Aeronautica bombed Harar and Jijiga as a prelude. Both cities were reduced to ruins even though Harar had been declared an "open city".

### Spanish Civil War

During the Spanish Civil War, the Nationalists under Francisco Franco made extensive use of aerial bombing on civilian targets. Nazi Germany gave aircraft to Franco to support the overthrow of the Spanish Republican government. The first major example of this came in November 1936, when German and Spanish aircraft bombed Republican-held Madrid; this bombardment was sustained throughout the Siege of Madrid. Barcelona and Valencia were also targeted in this way. On 26 April 1937, the German Luftwaffe (Condor Legion) bombed the Spanish city of Guernica carrying out the most high-profile aerial attack of the war. This act caused worldwide revulsion and was the subject of a famous painting by Picasso, but by the standards of bombings during World War II, casualties were fairly minor (estimates ranging from 500 to 1,500).
Shortly after, the front-page headlines of the Diario de Almeria, dated June 3, 1937, referred to the press in London and Paris carrying the news of the "criminal bombardment of Almeria by German planes".
Barcelona was bombarded for three days beginning on 16 March 1938, at the height of the Spanish Civil War. Under the command of the Italian dictator Benito Mussolini, Italian aircraft stationed on the island of Majorca attacked 13 times dropping 44 tons of bombs, aimed at the civil population. The medieval Cathedral of Barcelona suffered bomb damage and more than one thousand people died, including many children. The number of people injured is estimated to be in the thousands. Many others Spanish towns and cities were bombed by the German Legion Condor and the Italian Aviazione Legionaria among them Jaen, Durango, Granollers and Alicante.
The Spanish Republican government also used aerial bombings, but not as extensively, as they did not have as many planes available. Cities such as Valladolid, Granada, Sevilla, Zaragoza or Burgos were bombarded, killing some people. The biggest aerial attack against civil population was in Cabra, a small town away from the war front, and with no strategic value, that was bombed due to an error. 109 people were killed and more than 200 wounded. Planes coming from Barcelona launched three bombs against the Cathedral-Basilica of Our Lady of the Pillar on August 3, 1936. The bombs failed to detonate, but did damage one of the cupolas painted by Goya. The fact was considered a miracle, as, if the bombs had exploded, the eastern half of the Cathedral would have been completely destroyed.

### Second Sino-Japanese War

During the Manchurian Incident of 1931, the Japanese widely used airplanes to indiscriminately bomb key targets and cities, such as Mukden. After the Marco Polo Bridge Incident, the Imperial Japanese Army Air Service, in conjunction with the Imperial Japanese Navy Air Service, began relentlessly bombing Shanghai, Beijing (Peking), Tianjin (Tientsin) and several cities on the Chinese coast from the beginning of the Second Sino-Japanese War in 1937.
The bombing campaigns on Nanjing and Canton which started in September 1937 evoked protests from the Western powers culminating in a resolution by the Far Eastern Advisory Committee of the League of Nations. An example of the many expressions of indignation came from Lord Cranborne, the British Under-Secretary of State For Foreign Affairs:
   Words cannot express the feelings of profound horror with which the news of these raids had been received by the whole civilized world. They are often directed against places far from the actual area of hostilities. The military objective, where it exists, seems to take a completely second place. The main object seems to be to inspire terror by the indiscriminate slaughter of civilians ...

## World War II
### European Theater

At the beginning of World War II, bombing of cities prior to invasion was an integral part of Nazi Germany's strategy. In the first stages of war, the Germans carried out many bombings of towns and cities in Poland (1939), including the capital Warsaw (also bombed in 1944), with Wieluń being the first city destroyed by 75%. The Soviet Union also attempted strategic bombing against Poland and Finland, bombing Helsinki.
Rotterdam was bombed by Germany at 14 May 1940. The city had already surrendered an hour earlier and the attack was called off, but this did not reach the already flying bombers.
Germany began aerial bombing of British cities immediately after the British declaration of war on Germany in September 1939, while the first British bombing raids against Germany were on the night of 15/16 May 1940, with 78 bombers against oil targets, 9 against steelworks and 9 against marshalling yards, all military and industrial targets in the German hinterland. Oil remained the main British objective until the summer of 1941, although German cities and towns were regularly bombed from May 1940. Previous raids had been carried out by the RAF, but when targets were not found, the bombers returned without making an attack.
After the Fall of France, the Luftwaffe redirected its full attention to the United Kingdom. The scale of the attack increased greatly in July 1940, with 258 civilians killed, and again in August with 1,075 dead. During the night of 25 August, British bombers raided targets in and around Greater Berlin for the first time, in response to the misdirected bombing of Oxford Street and the West End by the Luftwaffe while it was bombing the London docks. On 4 September 1940 Hitler, frustrated by the RAF's superiority over the Luftwaffe and enraged by its bombing of German cities, decided to retaliate by bombing London and other cities in the UK. On 7 September the Luftwaffe began massed attacks on London. The bombing campaign was known in the UK as "the Blitz", and ran from September 1940 through to May 1941. The Coventry Blitz and the Belfast Blitz were two of the heaviest of all bombings by the Luftwaffe, killing 568–1,000 civilians of Coventry, killing over 1,100 civilians in Belfast, and destroying much of both city centres.
British bombing policy evolved during the war. In the beginning, the RAF was forbidden to attack urban targets in Germany due to the risk of accidental civilian casualties. Following a German attack on military targets in the Orkney Islands on 16 March 1940 that killed a civilian, the RAF mounted an attack on the seaplane base on the island of Sylt. The RAF began attacking transport targets west of the Rhine on the night of 10 May following the German invasion of the Low Countries, and military targets in the rest of Germany after the bombing of Rotterdam. On 9 September 1940 RAF crews were instructed that due to the "indiscriminate" nature of German bombing, if they failed to find their assigned targets they were to attack targets of opportunity rather than bring their bombs home. On the 15/16 December the RAF carried out its first area bombing attack (destroying 45% of the city of Mannheim), officially in response to the raid on Coventry.
In 1942, the goals of the British attacks were defined: the primary goal was the so-called "morale bombing", to weaken the will of the civil population to resist. Following this directive intensive bombing of highly populated city centers and working class quarters started. On 30 May 1942, the RAF Bomber Command launched the first "1,000 bomber raid" when 1,046 aircraft bombed Cologne in Operation Millennium, dropping over 2,000 tons of high explosive and incendiaries on the medieval town and burning it from end to end. 411 civilians and 85 combatants were killed, more than 130,000 had to leave the city.
Two further 1,000 bomber raids were executed over Essen and Bremen, but to less effect than the destruction at Cologne. The effects of the massive raids using a combination of blockbuster bombs and incendiaries created firestorms in some cites. The most extreme examples were caused by the bombing of Hamburg in Operation Gomorrah (45,000 dead), and the bombings of Kassel (10,000 dead), Darmstadt (12,500 dead), Pforzheim (21,200 dead), Swinemuende (23,000 dead), and Dresden (25,000 dead).
The Allies also bombed urban areas in the other countries, including occupied France (Caen) and the major industrial cities of northern Italy, like Milan and Turin. Some cities were bombed at the different times by the Luftwaffe and the Allies, for example Belgrade in Yugoslavia and Bucharest in Romania.
The Luftwaffe also bombed cities in the Soviet Union, destroying Stalingrad in a massive air raid at the start of the Battle of Stalingrad and bombing Leningrad during the siege of the city of 1941–1943. The Soviet bombing of the German cities was limited in comparison with the RAF bombing (destruction caused by the Soviet army was mainly due to the land artillery). The Soviet Air Force also bombed Budapest in Hungary.

### Asiatic-Pacific Theater

In the Asiatic-Pacific Theater, Japan continued to bomb Chinese cities and expanded its air operations towards others in Asia such as Singapore, Rangoon, and Mandalay. In the first few months of the war with the Western Powers, Japan projected its airpower on settlements as distant as Honolulu, Darwin, and Unalaska.
The capture of the Mariana Islands in 1944 enabled the United States Army Air Forces to reach the Japanese home islands using the Boeing B-29 Superfortress. The U.S. firebombed Tokyo on the night of March 9–10, 1945, and killed more than 100,000 people in the deadliest conventional bombing in history, known as Operation Meetinghouse. In a few hours, 100,000 people who were in Tokyo including civilians died either by the bombing or the conflagration that followed the bombing by 325 B-29's night attacks. The bombing was meant to burn wooden buildings and indeed the bombing caused fire that created a 50 m/s wind that is comparable to tornadoes. A total of 381,300 bombs amounting to 1783 tons, were used in the bombing.
After the successful Operation Meetinghouse raid, the USAAF went on to firebomb other Japanese cities in effort to pulverize the Japanese war industry and shatter Japanese civilian morale. From March to August 1945, the U.S. firebombing of 67 Japanese cities had killed 350,000 civilians. In addition, the atomic bombings of Hiroshima and Nagasaki killed 120,000 people.

## Since World War II
### Korean War

During the Korean War of 1950–1953, U.S.-led UN air forces heavily bombed the cities in North Korea and the North-occupied South Korea, including their respective capital cities. There were also plans to use nuclear weapons against North Korea and the People's Republic of China.

### Vietnam War

From 1965 to 1968, during the Vietnam War, the United States Air Force conducted an aerial campaign known as Operation Rolling Thunder. The campaign began with interdiction of supply lines in rural areas of southern North Vietnam but incrementally spread northward throughout the country. In 1966, restrictions against bombing the capital city of Hanoi and the country's largest port, Haiphong, were lifted, and they were bombed by the USAF and Navy. The bombing of the city centers continued to be prohibited. However, the South Vietnamese cities seized by the communists were bombed, including the former capital of Huế during the 1968 Tet Offensive.
The Republic of Vietnam Air Force bombed contested cities in South Vietnam in 1968, 1972 and 1975, while the Vietnam People's Air Force attacked Southern cities (including the capital city of Saigon) in 1975.

### Arab-Israeli Conflict

Israeli cities were bombed by Egyptian, Syrian and Jordanian aircraft during the 1948 Arab-Israeli war and the Six-Day War. The bombing included attacks on some of Israel's largest cities, such as Tel Aviv, Jerusalem and Haifa. The Lebanese capital of Beirut was attacked by the Israeli aircraft during the Siege of Beirut in 1982, and during the 2006 Lebanon War (using guided munitions). Israel also conducted air strikes targeting Palestinian targets during the Second Intifada, including against Hamas in Gaza.

### Wars in Afghanistan

In March 1979, in response to an uprising, the Khalq-control army of Democratic Republic of Afghanistan carpet-bombed the Afghanistan's third-largest city of Herat, causing massive destruction and some 5,000 to 25,000 deaths. Herat was also repeatedly bombed during the following Soviet involvement in the Afghan civil war.
Following the September 11, 2001 attacks, the U.S.-led coalition attacked the urban targets in Afghanistan using mainly precision-guided munitions (or "smart bombs"). The United States government maintains that it has a policy of striking only significant combatant targets while doing all possible to avoid what it terms "collateral damage" to civilians and non-combatants during the U.S.-led war in Afghanistan.

### Iran–Iraq War

Saddam Hussein's Iraq attacked civilian targets in Iranian cities in the War of the Cities during the Iran–Iraq War in the 1980s, with Iranians retaliating in kind (both sides soon switched to ballistic missile attacks). Iraqi aircraft also bombed the Iraqi Kurdistan city of Halabja in 1988 with conventional and chemical weapons in 1988, killing more than 5,000 people in the largest aerial poison gas attack in history.

### Somalia's campaign against Isaaq

In 1988 Somali Air Force aircraft conducted intense aerial bombardment of major Isaaq cities targeting civilian Isaaqs during its campaign against Somali National Movement in the north of the country. Civilians were also strafed by Somali Air Force aircraft as they were fleeing the aerial bombardment. The artillery shelling and aerial bombardment caused the deaths of estimated 50,000–200,000 Isaaq civilians, as well as the complete destruction of Somalia's second and third largest cities. It also caused up to 500,000 Somalis (primarily of the Isaaq clan) to flee and cross the border into Hartasheikh in Ethiopia as refugees in what was described as "one of the fastest and largest forced movements of people recorded in Africa", and resulted in the creation of the world's largest refugee camp then (1988), with another 400,000 being internally displaced. The scale of destruction led to Hargeisa being known as the 'Dresden of Africa'.

### Gulf War

The Iraqi Air Force attacked Kuwait City in 1990 and bombed their own cities during the 1991 uprisings in Iraq, targeting civilians with the use of bomb-carrying helicopters (use of airplanes was banned by the Coalition as part of the ceasefire agreement that ended hostilities of the Gulf War but not the war itself).
UN-led coalition aircraft attacked targets in Iraqi cities, including in the capital Baghdad and the largest southern city of Basra during Operation Desert Storm in 1991.
On 13 February 1991, a United States Air Force (USAF) warplane fired two laser-guided missiles at an air raid shelter in the Al-A'amiriya neighborhood of Baghdad, killing at least 408 civilians sheltering there. U.S. officials subsequently claimed that the shelter also served as a communications center for the Iraqi military. BBC correspondent Jeremy Bowen, who was one of the first television reporters on the scene, was given access to the shelter and claimed that he did not find any evidence of it being used by the Iraqi military. His claims were later contradicted by Iraqi general Wafiq al-Samarrai, who claimed that the shelter was used by the Iraqi Intelligence Service, and that Saddam Hussein had personally made visits to it. The day after the bombing of the shelter, a Royal Air Force (RAF) fighter jet fired two laser-guided missiles which were aimed at a bridge in Fallujah which was used as part of an Iraqi military supply line. The missiles malfunctioned and struck Fallujah's largest marketplace (which was situated in a residential area), killing between 50 and 150 non-combatants and wounding many more. After news of the mistake became public, an RAF spokesman, Group Captain David Henderson issued a statement noting that the missile had malfunctioned but admitted that the Royal Air Force had made an error.

### Yugoslav wars

At the beginning of the Yugoslav Wars, in Croatia (1991), the Yugoslav People's Army (JNA) carried out aerial bombing of Dubrovnik and Vukovar.
NATO's aerial bombing of FR Yugoslavia in 1999 included targeted aerial bombing throughout Serbia, notably of targets in Belgrade, Novi Sad and Niš. In addition to military casualties, there were at least 500 civilian casualties. Despite the NATO campaign appearing to violate NATO's charter, the UNSC rebutted the case on March 24 and March 26, 1999. In addition to purely military targets NATO targeted the national power grid (leaving many cities in the dark), water purification plants, oil refineries, fertilizer factories, and a petrochemical plant in Pancevo. The 78-day bombing campaign is assessed as having been an 'economic catastrophe', cutting the Yugoslav economy in half.

### Chechen wars

Post-Soviet Russia heavily bombed the Chechen capital of Grozny from the air with mostly unguided munitions (including fuel-air explosives) as well as bombarding it with a massive artillery barrages (1994–1995, 1996 and 1999–2000), killing thousands of people (some estimates say 27,000 civilians were killed during the 1994–1995 siege alone) including civilians during the First and Second Chechen Wars. Although the Russian pilots and soldiers were ordered to attack designated targets only, such as the Presidential Palace, due to their inexperience and lack of training, Russian soldiers and pilots bombed and shelled random targets inside the city. In 2003, the UN still called Grozny the most destroyed city on earth.

### Iraq War

In 2003 Invasion of Iraq, the U.S.-led coalition aircraft again bombed Iraq, including the Shock and Awe campaign of precision bombing of government targets in the city centers. From 2003 to 2011 and 2014 to 2018, coalition aircraft attacked Iraqi insurgent targets, including in urban locations like Najaf, Fallujah, Mosul, Basra, and Baghdad. There are frequent reports of civilian casualties, though it is often hard to distinguish guerrillas and civilians.

### Syria

Syrian MiG-23s bombed the city of Aleppo on 24 July 2012, the first use of aerial bombing in the Syrian Civil War. Over the course of the war, the Syrian government has dropped tens of thousands of bombs, mostly unguided barrel bombs, on the cities of Aleppo, Damascus, Homs, Hama, Deir ez-Zor, Hasakah, Daraa, Darayya, and Al-Bab.

### Ukraine

Russia has strategically bombed the Ukrainian civilian power grid, with low or null military purpose, in order to weaken Ukraine resistance or distract it from attacking and taking back Russian occupied territories. This is in addition to Russian bombing of civilian buildings such as apartment blocks, retail shops, offices, schools, hospitals, etc.

### Gaza

During the Israel–Hamas war, Israeli airstrikes damaged or destroyed Palestinian refugee camps, schools, hospitals, mosques, churches, and other civilian infrastructure. By late April 2024 it was estimated that Israel had dropped over 70,000 tons of bombs over Gaza, surpassing the bombing of Dresden, Hamburg, and London combined during World War II.

### Other conflicts

Budapest was attacked by intense Soviet air strikes in 1956 during the Hungarian Revolution. A year before, on 16 June 1955, Casa Rosada, the Argentine government seat at Buenos Aires, was the target of four waves of fighter-bombers during a military uprising to overthrow Juan Perón. Fourteen-tons of bombs scattered on a wide area, killing hundreds of civilian passers-by as well as 11 soldiers. In 2008, the cities of Tskhinvali and Gori were hit by the Georgian and Russian aircraft during the war in Georgia.

## International law

Air warfare, theoretically, must comply with laws and customs of war, including international humanitarian law by protecting the victims of the conflict and refraining from attacks on protected persons.
These restraints on aerial warfare are covered by the general laws of war, because unlike war on land and at sea – which are specifically covered by rules such as the 1907 Hague Convention and Protocol I additional to the Geneva Conventions, which contain pertinent restrictions, prohibitions and guidelines – there are no treaties specific to aerial warfare.
To be legal, aerial operations must comply with the principles of humanitarian law: military necessity, distinction, and proportionality: An attack or action must be intended to help in the defeat of the enemy; it must be an attack on a legitimate military objective, and the harm caused to protected civilians or civilian property must be proportional and not excessive in relation to the concrete and direct military advantage anticipated.