US aircraft and artillery Foreign intervention in behalf of Syrian rebels U.S.-led intervention against ISIL The Battle of Khasham, also known as the Battle of Conoco Fields, was a military engagement of the Syrian civil war fought on 7 February 2018 near the towns of Khasham and Al Tabiyeh in the Deir ez-Zor Governorate, Syria.

[13] As unconfirmed accounts of casualties among Russian Wagner Group mercenaries in the strike emerged, the incident was billed by media as "the first deadly clash between citizens of Russia and the United States since the Cold War".

[32] This intent was, in mid-January 2018, clearly broadcast by Secretary of State Rex Tillerson, who said the Trump administration would maintain an open-ended military presence in Syria to counter Iranian influence and ensure the departure of Syrian President Bashar al-Assad.

[7] On 22 February 2018, The Washington Post cited unnamed sources in U.S. intelligence as alleging that the communications intercepted days before and after the incident between Russian businessman Yevgeny Prigozhin, who was believed to finance Wagner, and senior Syrian officials, such as Mansour Fadlallah Azzam, as well as Kremlin officials, suggested that Prigozhin had "secured permission" from an unspecified Russian minister to go ahead with a "fast and strong" move in early February and was awaiting approval from the Syrian government.

[38][39][40] According to the U.S. military's official statement, around 10 p.m. local time on the night of 7 February 2018, a force of 500 pro-government fighters consisting of local militiamen, Syrian Army regulars, Shia militants from Liwa Fatemiyoun and Liwa Zainebiyoun, and reportedly Russian private military contractors, launched an assault on an SDF headquarters near Khasham.

[21][13] Supported by T-72 and T-55 tanks, the pro-government troops first shelled the SDF base with artillery, mortars, and rockets in what U.S. military officials described as a "coordinated attack".

[6][14][7] According to the U.S. military, the presence of U.S. special operations personnel in the targeted base elicited a response by coalition aircraft, including AC-130 gunships, F-22 Raptor and F-15E Strike Eagle fighter jets, MQ-9 Reaper unmanned combat aerial vehicles, AH-64 Apache attack helicopters, and B-52 bombers.

[15] Three weeks after the incident, Germany's Der Spiegel published their own investigative report based on evidence gleaned from multiple first-hand sources (participants and witnesses) in the area.

[2] At the time, Russia and the United States had an agreement that no more than 400 pro-Syrian government fighters could be in the Syrian-government controlled salient on the river's east bank.

At around 5 a.m. on 7 February 2018, around 250 of these fighters attempted to cross the Euphrates over a military pontoon bridge located to the southeast of both the Deir ez-Zor Airport and the SDF base near Khasham.

[2] Later that same day, under the cover of darkness, about twice as many pro-Syrian government fighters successfully crossed a different bridge located northeast of Deir ez-Zor Airport.

[17] The remaining 23 pro-government personnel, including 15 Russians PMCs, were not killed in the airstrikes, but instead caught in a booby-trapped explosion at an arms depot at Tabiyet Jazira.

[54] Additionally, a Russian military doctor, a leader of a PMC-linked paramilitary Cossack organization, and a source with ties to Wagner claimed 80–100 PMCs were killed and 200 wounded.

[56][70] Irek Murtazin of Novaya Gazeta and analyst Yury Barmin speculated that the Russian Ministry of Defence may have wittingly let the Wagner unit find itself in harm's way.

[26][71] On 12 February 2018, Grigory Yavlinsky called on President Vladimir Putin to present an account of whether any Russian military forces had been involved in the battle.

[72][73][74] Meanwhile, Russia's government-run news agency TASS acknowledged, with reference to a Cossack organisation, the death in a battle near Deir ez-Zor of a Russian "volunteer", sotnik Vladimir Loginov, a resident of the Kaliningrad Region.

[75] The news media also named four more Russians killed during the strike, including Kirill Ananiev, a veteran member of the banned National Bolshevik Party.

[76][77] News outlets also noted that Vladimir Putin abruptly cancelled most of his previously announced engagements scheduled for 12 and 13 February, his press service citing ill health, and instead had a secret conference with his top military chiefs;[78][79] he also had a telephone conversation with U.S. president Donald Trump on 12 February, with no details revealed.

[80][81] Russian politician Viktor Alksnis, authorised representative of Communist Party presidential election candidate Pavel Grudinin, voiced an opinion on Radio Liberty that the U.S. strike was designed as a demonstration of the U.S.'s military superiority and dominance in the region, and that it might have serious geopolitical consequences for Russia.

[82] On 14 February, presidential spokesperson Dmitry Peskov admitted the possibility that some Russian citizens who were not part of Russia's armed forces were in Syria, but dismissed reports of mass casualties as false.

[93][94] Following the statement, the foreign ministries of Belarus and Kazakhstan were reported to be checking if there were casualties among their countries' citizens, but stated they had no information to confirm that Belarusians or Kazakhstanis had been killed or wounded.

[96] Several Russian online news outlets, citing Syria's media and ex-KGB officer Igor Panarin, published unconfirmed reports that the Su-57 fighters, deployed to Syria since February 2017, had taken part in strikes against rebel targets in Eastern Ghouta, killing about ten U.S. personnel (military instructors) as well as other Western countries' instructors stationed in the rebel stronghold, despite the lack of known U.S. military presence in the region; the strikes were presented as retaliation for the U.S. attack at Khasham.

[100][101] Earlier, Komsomolskaya Pravda military correspondent Viktor Baranets [ru] was cited as saying that according to his information, the Su-57s had done "excellent" work carrying out their mission in Eastern Ghouta.

[104] On 10 February 2018, a U.S. MQ-9 Reaper drone destroyed a T-72 tank of pro-government forces in an airstrike near the Al Tabiyeh gas field.