Airstrike on Saeqa military camp near Deir ez-Zor

According to the General Staff of the Syrian Army, on December 6, 2015, from 19:40 to 19:55, aviation of the Western coalition made an airstrike on a field camp of the 168th Brigade of the 7th Division of the governmental troops of the Syrian Armed Forces located 2 km to the west of Deir ez-Zor.

The strike resulted in destruction of 3 infantry fighting vehicles, 4 automobile vehicles equipped with large-caliber machine guns (DShK); 12 people were injured, 4 were killed. (Source)

Initial reports
"The consensus among the Syrian Arab Army soldiers is that the warplane was flying west towards the village of ‘Ayyash before 9 missiles struck their positions. According to the Shaytat Tribesmen, the tribes of Abukamaal (eastern Deir Ezzor) reported coalition airstrikes above their city just a few minutes they struck ‘Ayyash. Following the attack on ‘Ayyash in Deir Ezzor’s northern countryside, the U.S. led Coalition warplane struck the ISIS stronghold of Al-Shadadi in southern Al-Hasakah before completing their mission."
 * [Al Masdar news: It is reported that US-led coalition planes hit Syrian Army position], killing some soldiers, in a rare or first incident of such sort. Unclear why they would do this on the eve of political negotiations; possibly done in error.
 * Syria conflict: 'Coalition strike' kills government forces - BBC News, December 7, 2015
 * ''A US-led coalition air strike on an army camp in Syria kills three soldiers, the Syrian government says, condemning the act of "flagrant aggression".
 * Four Syrian Soldiers Killed in US-Led Coalition Airstrike - Sputnik, 07.12.2015 (cites "sources," no government confirmation, 3 killed)
 * US-led coalition airstrike on SAA position in Deir Ezzor (Photos) - AlManarTV, December 7, 2015 (original) Photos of serious destruction within the base - this would be quite an error.
 * Details Behind the U.S. Coalition’s Airstrike that Killed 3 Syrian Soldiers in Deir Ezzor, Al Masdar News, December 9, 2015

Western denial

 * Syria conflict: Coalition denies air strike on army camp - BBC News, December 7, 2015 (Updated)
 * ''The Syrian government has said three of its soldiers have been killed in a US-led coalition air strike, but the coalition has denied responsibility.
 * US-Led Coalition Denies Involvement In Airstrike That Killed 4 Syrian Soldiers In Deir Ez-Zor Province - Sneha Shankar, IB Times, December 7, 2015
 * ''UPDATE: 4:23 a.m. EST -- The U.S.-led coalition, which was suspected to have killed four Syrian soldiers in an airstrike in the western Deir ez-Zor province, has denied any involvement in the attack, Al Jazeera reported on Monday.

Accusing Russia

 * Russian strike hits Syria army camp: U.S. official - Reuters, Beirut, 7 December 2015
 * Russia likely conducted deadly airstrike on Syrian military base, US official says - FoxNews, December 07, 2015
 * U.S. Officials Deny Bombing the Syrian Army in Deir Ezzor: Russians Blamed - LEITH FADEL, December 7, 2015
 * New York Times
 * A senior United States official later attributed any deaths and any damage to the Syrian base to what he called “a screw-up” by the Russians ... “We’ve got a radar track showing a Backfire bomber flying directly over the town that the Syrians named a few minutes before the first claims that we killed some Syrian troops,” the American official said, speaking on the condition of anonymity to discuss operational details.

It's not clear how the radar track revealed the exact model of aircraft, or if they learned that some other way.

Syrian and Russian claims

 * 4 US-led coalition jets seen over Deir ez Zor in Syria on day govt troops attacked - Moscow - RT, December 9, 2015
 * ''Four Western coalition warplanes were spotted over the Deir az-Zor area in Syria on December 6, when a Syrian Army camp came under attack. No Russian warplanes were in the region, says the Russian Defense Ministry.

Analysis

 * Did Members of the US-Led Coalition Carry Out an Air Strike to Help ISIS? Russia Implies They Did - Alexander Mercouris, Russia Insider, December 10, 2015
 * ''Russian statement appears to implicate aircraft from two member states of the US led coalition in the air strike on the Syrian military base in Deir az-Zor