Friendly fire Friendly fire is an attack by a military force on friendly forces while attempting to attack the enemy , either misidentifying the target as hostile , or due to errors or inaccuracy . Such attacks often cause injury or death . Fire not intended to attack the enemy , such as negligent or malicious discharge , or deliberate firing on one ' s own troops for disciplinary reasons , is not called friendly fire . Nor is unintentional harm to non - combatants or structures , sometimes referred to as " collateral damage " . Use of the term " friendly " in a military context for allied personnel or materiel dates from the First World War , often for shells falling short . The term " friendly fire " was originally adopted by the United States military . Many North Atlantic Treaty Organization ( NATO ) militaries refer to these incidents as blue on blue , which derives from military exercise s where NATO forces were identified by blue pennants and units representing Warsaw Pact forces by orange pennants . Addressing friendly fire . Friendly fire is often seen as an inescapable result of combat , and because it only accounts for a small percentage of casualties , can often be dismissed as irrelevant to the outcome of a battle . The effects of friendly fire , however , are not just material . Troops expect to be targeted by the enemy , but being hit by their own forces has a huge negative impact on morale . Forces doubt the competence of their command , and its prevalence makes commanders more cautious in the field . Attempts to reduce this effect by military leaders generally come down to identifying the causes of friendly fire and overcoming repetition of the incident through training , tactics and technology . Causes . Friendly fire arises from the " fog of war " – the confusion inherent in warfare . Friendly fire that is the result of apparent recklessness or incompetence may be improperly lumped into this category . The concept of a fog of war has come under considerable criticism , as it can be used as an excuse for poor planning , weak or compromised intelligence and incompetent command . Errors of position occur when fire aimed at enemy forces may accidentally end up hitting one ' s own . Such incidents are exacerbated by close proximity of combatants and were relatively common during the First and Second World Wars , where troops fought in close combat and targeting was relatively inaccurate . As the accuracy of weapons improved , this class of incident has become less common but still occurs . Errors of identification happen when friendly troops are mistakenly attacked in the belief that they are the enemy . Highly mobile battles , and battles involving troops from many nations are more likely to cause this kind of incident as evidenced by incidents in the first Gulf War , or the shooting down of a British aircraft by a U . S . Patriot battery during the Invasion of Iraq . In the Tarnak Farm incident , four Canadian soldiers were killed and eight others injured when a U . S . Air National Guard Major dropped a 500 lb ( 230 kg ) bomb from his F - 16 onto the Princess Patricia ' s Canadian Light Infantry regiment which was conducting a night firing exercise near Kandahar . Another case of such an accident was the death of Pat Tillman in Afghanistan , although the exact circumstances of that incident are yet to be definitively determined . In preparation for the invasion of Normandy " invasion stripes " were painted on Allied aircraft to assist identification . Similar markings had been used when the Hawker Typhoon was first introduced into use as it was otherwise very similar in profile to a German aircraft . Late in the war the " protection squadron " that covered the elite German jet fighter squadron as it landed or took off were brightly painted to distinguish them from raiding Allied fighters . A number of situations can lead to or exacerbate the risk of friendly fire . Poor terrain and visibility are major factors . Soldiers fighting on unfamiliar ground can become disoriented more easily than on familiar terrain . The direction from which enemy fire comes may not be easy to identify , and poor weather conditions and combat stress may add to the confusion , especially if fire is exchanged . Accurate navigation and fire discipline are vital . In high - risk situations , leaders need to ensure units are properly informed of the location of friendly units and to issue clear , unambiguous orders , but they must also react correctly to responses from soldiers who are capable of using their own judgement . Miscommunication can be deadly . Radios , field telephones , and signalling systems can be used to address the problem , but when these systems are used to co - ordinate multiple forces such as ground troops and aircraft , their breakdown can dramatically increase the risk of friendly fire . When allied troops are operating the situation is even more complex , especially with language barriers to overcome . Solutions . Training . Most militaries use extensive training to ensure troop safety as part of normal co - ordination and planning , but are not always exposed to possible friendly - fire situations to ensure they are aware of situations where the risk is high . Difficult terrain and bad weather cannot be controlled , but soldiers must be trained to operate effectively in these conditions , as well as trained to fight at night . Such simulated training is now commonplace for soldiers worldwide . Avoiding friendly fire can be as straightforward as ensuring fire discipline is instilled in troops , so that they fire and cease firing when they are told to . Firing ranges now also include ' Don ' t Fire ' targets . The increasing sophistication of weaponry , and the tactics employed against American forces to deliberately confuse them has meant that while overall casualties have fallen for American soldiers in the late 20th and 21st centuries , the overall percentage deaths due to friendly fire in American actions have risen dramatically . In the 1991 Gulf War , most of the Americans killed by their own forces were crew members of armored vehicles hit by anti - tank rounds . The response in training includes recognition training for Apache helicopter crews to help them distinguish American tanks and armored vehicles at night and in bad weather from those of the enemy . In addition , tank gunners must watch under fire in drills for " friendly " robotic tanks that pop out on training courses in California ' s Mojave Desert . They also study video footage to help them recognize American forces in battle more quickly . Technology . Improved technology to assist in identifying friendly forces is also an ongoing response to friendly fire problems . From the earliest days of warfare , identification systems were visual and developed into extremely elaborate suits of armour with distinctive heraldic patterns . When radar was developed during World War II , IFF systems to identify aircraft developed into a multitude of radio beacons . Correct navigation is vital to ensuring units know where they are in relation to their own force and the enemy . Efforts to provide accurate compasses inside metal boxes in tanks and trucks has proven difficult , with GPS a major breakthrough . Government contractors are rushing to perfect infra - red and carbon dioxide laser beacons that can be mounted on armored vehicles and that will identify themselves to their own forces . Other technological changes include hand - held navigational devices that use satellite signals , giving ground forces the exact location of enemy forces as well as their own . The use of infra - red lights and thermal tape that are invisible to observers without night - goggles , or fibres and dyes that reflect only specific wavelengths are still in their infancy , but may prove to be key identifiers for friendly infantry units at night . There is also some development of remote sensors to detect enemy vehicles – the Remotely Monitored Battlefield Sensor System ( REMBASS ) uses a combination of acoustic , seismic vibration , and infrared to not just detect , but identify vehicles . Tactics . Some tactics make friendly fire virtually inevitable , such as the practice of dropping barrages of mortars on enemy machine gun posts in the final moments before capture . This practice continued throughout the 20th century since machine guns were first used in World War I , and the high friendly fire risk has generally been accepted by troops since machine gun emplacements are tactically so valuable , and at the same time so dangerous that the attackers wanted them to be shelled , considering the shells far less deadly than the machine guns . Tactical adjustments include the use of " kill boxes " , or zones that are placed off - limits to ground forces while allied aircraft attack targets , which goes back to the beginning of military aircraft in World War I . The shock and awe battle tactics adopted by the American military – overwhelming power , battlefield awareness , dominant maneuvers , and spectacular displays of force – are employed because they are believed to be the best way to win a war quickly and decisively , reducing casualties on both sides . However , if the only people doing the shooting are American , then a high percentage of total casualties are bound to be the result of friendly fire , blunting the effectiveness of the shock and awe tactic . It is probably the fact that friendly fire has proven to be the only fundamental weakness of the tactics that has caused the American military to take significant steps to overturn a blasé attitude to friendly fire and assess ways to eliminate it . Historical examples . There have been many thousands of friendly fire incidents in recorded military history , accounting for an estimated 2 % to 20 % of all casualties in battle . The examples listed below illustrate their range and diversity , but this does not reflect increasing frequency . The " rate " of friendly fire , once allowance has been made for the numbers of troops committed to battle , has remained remarkably stable over the past 200 years . Vietnam War . It has been estimated that there may have been as many as 8 , 000 friendly fire incidents in the Vietnam War ; one was the inspiration for the book and film " Friendly Fire " .