2023 invasion of Hungary (1941: Barbarossa Victory)

* Hungarian president Takács Áron announces military operation to quell separatists in northern Slovakia
* Hungarian Communist Party declares an offensive against the Hungarian government
* The United States and a coalition of European nations declare war on Hungary after alleged Hungarian attacks against Poland
 "Heavy" civilian casualties reported in Bardejov and NámestovoAt least 14 Polish civilians killed in missile attacks on border villages

Early on the morning of 9 October 2023, Hungarian forces invaded the territory of the Slovak National Session in what marked the largest escalation of the War in Slovakia since a ceasefire was signed between the National Session and Hungarian forces in 2006. Tensions had gradually escalated between the two sides throughout the late 2010s and early 2020s, perhaps most severely in March of 2018 when there was a series of skirmishes between Hungarian and Slovak forces at the demarcation line set out in the 2006 ceasefire, and as early as June of 2023 a buildup of Hungarian forces along the demarcation line was noted, leading to concerns of a potential resumption of conflict, though Hungarian officials denied that any offensive was being planned in the region.

On 21 September 2023, Slovak separatists announced that they had downed a Hungarian fighter jet in Vitanová that had violated the National Session's airspace, with both the pilot and copilot killed in what international observers noted as the most severe confrontation between Hungarian and Slovak forces since the 2018 crisis. On October 5, American intelligence claimed that approximately 20,000 Hungarian troops had assembled near the demarcation line, and President Tim Kaine the following day warned the Hungarian government that an offensive in Slovakia would have "massive consequences". On 7 October, Slovak forces claimed that Hungarian troops had entered the demilitarized zone near Štrba in a violation of the 2006 ceasefire agreement, and the following day claimed that Hungarian forces had occupied the city of Poprad, which had been demilitarized and declared a neutral zone in the 2006 ceasefire agreement.

Shortly before 2 am local time on 9 October, it was reported that Hungarian forces had begun a bombardment of Námestovo and Bardejov, resulting in substantial civilian casualties in both towns. Less than an hour later, Miloslav Skalický, the president of the Slovak National Session confirmed that Hungarian forces had attacked Slovak troops at Krivá and Vysoké Tatry, two settlements behind the demarcation line. There was also unconfirmed reports around this time of fighting in the vicinity of Malá Franková and Pribylina, indicating that a full-scale Hungarian offensive was underway. Hungarian president Takács Áron announced that a military operation had been commenced in northern Slovakia around 3 am local time, with the stated goal of "restoring order and sanity to the region". While fighting initially was only between Hungary and the Slovak National Session, it rapidly escalated in the hours after the invasion as Hungarian troops launched missiles into Polish territory, killing 14 and prompting a massive Polish military response. This was followed by American troops being prepared for potential conflict with Hungary as President Tim Kaine promised to defend Poland "by any means necessary".

The situation rapidly escalated after the Polish government alleged that Hungarian troops had infiltrated Polish territory early on 10 October, prompting them to invoke the Treaty of Prague, resulting in a large-scale military response against Hungary from much of Eastern Europe. United States president Tim Kaine announced the beginning of a military operation to "disarm Hungary" that evening.

## Timeline

*See also: Timeline of the War in Slovakia (1999-present)*

### Before 9 October 2023

* 21 September 2023 - Slovak separatists announce that they have downed a Hungarian fighter jet in the vicinity of Vitanová, killing two Hungarian military personnel.
* 23 September 2023 - Hungarian government officials denounce the Slovak separatists for shooting down the fighter jet, claiming that they were "trying to ignite the conflict".
* 5 October 2023 - American intelligence claims that 20,000 Hungarian troops have gathered near the 2006 demarcation line.
* 6 October 2023 - United States president Tim Kaine warns the Hungarian government that any invasion of the National Session would have "massive consequences".
* 7 October 2023 - Sources affiliated with the Slovak National Session claim that Hungarian troops had entered the demilitarized zone near Štrba.
* 8 October 2023 - Poprad, previously in a demilitarized neutral zone, is reportedly occupied by Hungarian troops.

### 9 October 2023

* 11 pm GMT (1 am local time) - Hungarian troops commence a massive bombardment of Námestovo and Bardejov shortly before 2 am local time (12 am GMT). Civilian casualties are reported to be heavy.
* 11:20 pm GMT (1:20 am local time) - Hungarian troops attack Slovak troops at Krivá, though Slovak forces reportedly manage to prevent Hungarian forces from taking the village.
* 11:35 pm GMT (1:35 am local time) - Slovak and Hungarian forces face off in the town of Vysoké Tatry, with Slovak forces claiming heavy Hungarian casualties.
* 12:45 am GMT (2:45 am local time) - Hungarian president Takács Áron confirms the initiation of a military operation in Slovakia.
* 2:45 am GMT (4:45 am local time) - Hungarian forces launch a missile attack on the Polish border village of Chochołów, killing at least 14.
* 3:30 am GMT (5:30 am local time) - Polish president Rafał Trzaskowski orders a general mobilization of the Polish Armed Forces. Air strikes are launched on Hungarian air and military bases by the Polish Air Force.
* 5:00 am GMT (7:00 am local time) - Hungarian forces are confirmed to have breached the demarcation line and reached Vasiľov, rapidly advancing on Námestovo. Polish troops enter the territory of the Slovak National Session.
* 9:00 am GMT (11:00 am local time) - Martial law is declared in Hungary.
* 11:30 am GMT (1:30 pm local time) - Hungarian forces secure Vysoké Tatry and surrounding areas. Hungarian forces are reportedly ambushed by Slovak insurgents at Levoča.
* 2:45 pm GMT (4:45 pm local time) - Hungarian troops reach Ťapešovo, less than 5 km from Námestovo. American troops in Eastern Europe are placed at maximum combat readiness as preparations for a conflict with Hungary begin.
* 4:00 pm GMT (6:00 pm local time) - American president Tim Kaine delivers a press conference in which he condemns the Hungarian offensive, and pledges to use "any means necessary" to defend Poland.
* 5:00 pm GMT (7:00 pm local time) - Miksa Natália, General Secretary of the Hungarian Communist Party calls for an offensive to "crush the fascist pretenders".
* 7:45 pm GMT (9:45 pm local time) - Slovak media claim that Hungarian troops were pushed back from Ťapešovo after a brief engagement between Hungarian and Slovak troops, claiming heavy Hungarian casualties.
* 9:00 pm GMT (11:00 pm local time) - The Hungarian government orders a general mobilization of their reserve troops (numbering an estimated 2 million) in response to what they claim to be an impending invasion.
* 9:20 pm GMT (11:20 pm local time) - Hungarian troops attack Polish troops at Konská.

### 10 October 2023

* 12:30 am GMT (2:30 am local time) - A buildup of Romanian forces at the border with Hungary is confirmed.
* 12:45 am GMT (2:45 am local time) - Russian and British leaders reaffirm their support for any offensive against Hungary.
* 3:45 am GMT (5:45 am local time) - The Polish government claims that Hungarian forces ambushed Polish troops at Kościelisko, marking the first incursion into Polish territory of the war. An emergency meeting is convened by Polish leadership on whether or not to invoke the Treaty of Prague, which would bring all of Eastern Europe into war with Hungary.
* 4:30 am GMT (6:30 am local time) - The United States Congress passes a resolution authorizing the use of military force against Hungary.
* 9:30 am GMT (11:30 am local time) - Slovak separatists claim to have captured Brezno.
* 11:45 am GMT (1:45 pm local time) - Members of the Hungarian Communist Party confirm a raid on a military barracks at Fehérvár in the first engagement within Hungary itself.
* 3:30 pm GMT (5:30 pm local time) - Slovak forces claim to have expelled the Hungarians from the Námestovo area, reaching as far south as Dolný Kubín.
* 6:00 pm GMT (8:00 pm local time) - Polish troops enter Slovakia at Pčoliné, fighting the Hungarian troops stationed in the area.
* 7:45 pm GMT (9:45 pm local time) - Slovak insurgents claim to have forced a disorganized Hungarian garrison from Žilina, the fourth-largest city in the country.
* 10:00 pm GMT (12:00 am local time) - United States president Tim Kaine delivers a national address in which he officially declared a military operation in Hungary, the invasion of Hungary begins.
* 10:15 pm GMT (12:15 am local time) - Romania claims to have captured Kovászna after a several-hour battle with Hungarian forces, marking the first major battle on Hungarian soil of the war.
* 10:45 pm GMT (12:45 am local time) - American intelligence claims that over 500,000 Hungarian troops had been mobilized since the 7th, however that the Hungarian Air Force had been crippled by intense air strikes on Hungarian air bases.