A suspected US-led coalition air strike has killed four Syrian military personnel, according to a monitoring group.
The strike took place in Deir al-Zour province, which is largely held by the jihadist group Islamic State, said the Syrian Observatory for Human Rights.
If confirmed, it would be the first coalition strike to have killed Syrian government forces.
The UK-based Syrian Observatory said 13 military personnel were also wounded.
The strike hit part of the Saeqa military camp, near the town of Ayyash, it said.
The IS controls most of the province, including almost all of its capital, Deir al-Zour.
A separate strike believed to have been carried out by the coalition in the city overnight killed a woman and two of her children, the Syrian Observatory said.
Deir al-Zour province links Islamic State’s de facto capital in Raqqa with territory controlled by the group in Iraq. The area’s oilfields are a major source of revenue for IS.