Moscow: The Russian military on Sunday said armed groups had attacked a Syrian town from Turkish territory, adding it had demanded an explanation from the United States.
"Overnight from February 27 to 28 the Russian centre for the reconciliation of the warring parties in Syria received information about an attack from Turkish territory on the Syrian town of Tal Abyad by armed units using large-scale artillery," said the chief of the centre, Lieutenant General Sergei Kuralenko.
"This was subsequently verified and confirmed through several channels including representatives of the Syrian Democratic Forces," Kuralenko was quoted as saying by Russian news agencies from the Hmeimim airbase.
The Syrian Democratic Forces is a US-backed Kurdish-Arab alliance.
"The Russian centre has turned for an explanation to the Amman-based US centre for reconciliation," Kuralenko added, stressing that Turkey was a member of a US-led coalition.
No other details were provided by the Russian side.
According to the Syrian Observatory for Human Rights, the Kurdish forces and their Arab allies successfully pushed back a fierce IS offensive by last night with backing from the US-led coalition.
In a statement published late yesterday, the Kurdish People's Protection Units (YPG) accused a group of "IS mercenaries" of launching an attack on Tal Abyad from Raqa to the south and from Turkish territory to the north late Friday.
They said they were able to repel the attack but that clashes were ongoing.
A ceasefire brokered by Moscow and Washington took effect from 2200 GMT Friday and was largely holding today.
There was no immediate confirmation of the Russian report from Turkey.
Turkey said earlier the ceasefire deal was not binding for Ankara if its national security was threatened.