The U.S. military has said it stopped an air raid against Islamic State (IS) militants in eastern Syria after Russian officials said it may have bombed Syrian army troops.
The U.S. military said in a statement on September 17 that "coalition forces would not intentionally strike" Syrian forces.
"The coalition air strike was halted immediately when coalition officials were informed by Russian officials that it was possible the personnel and vehicles targeted were part of the Syrian military," the statement said.
The Syrian military reported earlier that warplanes from the U.S.-led coalition battling IS militants in Syria and Iraq had struck a Syrian Army base in the eastern Deir al-Zor Province.
The Syrian military said in a statement issued on September 17 that the multiple air strikes had resulted in casualties and damage to military equipment.
Russian military officials said four air strikes had killed 62 Syrian soldiers and wounded about 100 others.
The Syrian Observatory for Human Rights said at least 80 Syrian soldiers had been killed in the bombing.
Syrian media did not report how many soldiers had been killed and injured.
But the London-based monitoring group said it was unable to say who carried out the air strikes. It said Russian jets had been carrying out bombing raids in the area at the same time.
The Syrian troops had been involved in a fierce fight with IS militants at Jebel Tharda, which is near the Deir al-Zor air base where the attack on the Syrian forces occurred.
The military added that the aerial attack had allowed Islamic State (IS) militants to advance on a hill that overlooks the Syrian Army's air base.
The statement called the air strikes "a serious and blatant attack on Syria and its military" and said they represent "firm proof of the U.S. support of [IS] and other terrorist groups."
The U.S.-led coalition began its bombing campaign against Islamist fighters in Syria and Iraq two years ago.
Russia and the United States brokered a cease-fire on September 12, but both sides have criticized the other for not following through on the agreements made in the cease-fire, including allowing humanitarian aid to people besieged in the city of Aleppo and other nearby areas.
At least 250,000 people are estimated to have been killed since the start of Syria's civil war in 2011. Millions of others have fled their homes.