The Britain-based Syrian Observatory for Human Rights, a war monitor, said IS fighters launched two new attacks in Deir el-Zour on Saturday near the town of Mayadeen and the town of Boukamal near the Iraqi border. No US troops were harmed, but one allied Syrian fighter was wounded, the report said.
Four Russian soldiers have been killed by militants in Syria's eastern Deir Ezzor province, the defence ministry said on Sunday.
At first, Russian officials said only four Russian citizens - but perhaps dozens more - had been killed; a Syrian officer said around 100 Syrian soldiers had died.
The defense Ministry reported that the fighting lasted about an hour, the result was eliminated 43 militants.
"It killed 35 fighters of Pro-government forces, including at least nine Russians". All 26 Syrians killed were claimed to be Syrian military forces according to the statement. Five other Russians were injured and two died later of their wounds, the defence ministry said. Two military advisers were killed on the spot, two other servicemen succumbed to injuries at a hospital.More news: Subtropical Storm Alberto forms; watches issued for U.S., Mexico, Cuba
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The Russian ministry said the dead were military advisers attached to a Syrian army unit in the Deir ez-Zor.
Russian Federation has lost about 90 personnel in the civil war.
The worldwide group Conflict Intelligence Team said up to six Russian soldiers could have been killed in the attack, quoting social media reports of a funeral for a Russian soldier that took place in the Western Russian city of Smolensk this week.
The very best casualties have been in March, when a transport airplane crashed at Hmeimim airbase the place Moscow's airforce is predicated, killing all 39 individuals on board.
Vladimir Putin, Russian President ordered an "important portion" of Moscow's armed occurrence in Syria to start extracting from the state in December.