Rising tensions between world powers could lead to a "full-blown military escalation" in Syria, UN Secretary-General Antonio Guterres warned on Friday.
Guterres urged the Security Council to "act responsibly in these dangerous circumstances," according to AFP.
However, early on Friday, Turkish President Recep Tayyip Erdogan said Russia-US tensions over Syria appeared to be easing. Moscow and Washington had traded bitter accusations over potential American military action.
"It seems that with the latest developments, the atmosphere has eased somewhat," Erdogan told reporters in Istanbul. "Our talks continue and will continue," he said.
(With inputs from agencies)