Syrian-Kurdish YPG fighters appear to be reinforcing the Syrian city of Manbij, captured this month from Islamic State, with weapons and personnel, regional security sources told Reuters on Monday.
Manbij, on the west bank of the Euphrates River, was captured by the Syrian Democratic Forces alliance, which includes the Kurdish YPG militia, in an offensive backed by the United States.
A Syrian rebel commander said on Sunday that Turkey-backed rebels aimed to capture the city from Kurdish-allied forces.
Sources told Reuters that trucks and minibuses loaded with weapons, equipment and personnel were moving from east to west in northern Syria, leading them to believe the YPGwas reinforcing Manbij.
The YPG said last week its fighters had withdrawn from the Manbij area, saying their presence there could not be used as a pretext for an attack. The YPG could not be reached for comment.
Turkey and its Syrian rebel allies seized territory controlled by Kurdish-aligned forces on Sunday, the fifth day of a cross-border campaign that a monitoring group said had killed at least 35 villagers.
Turkish warplanes roared into northern Syria at daybreak on Sunday and artillery pounded what security sources said were sites held by the YPG militia, after the Syrian Observatory for Human Rights reported fierce overnight fighting around two villages.
Turkey has said 25 Kurdish militants were killed in its air strikes and denied there were civilian casualties.