The Islamic State group on Tuesday claimed an attack on US-backed forces in the northern Syrian city of Manbij, days after their "caliphate" was declared defeated.
Syrian troops deployed in support of Kurdish forces around a strategic northern city on Friday, in a shift of alliances hastened by last week's announcement of a US military withdrawal.
Turkish-backed Syrian forces have reinforced the area around the town of Manbij, a rebel spokesman said on Monday, as they prepare for a withdrawal of US troops following Washington's surprise decision to pull out of Syria.
The Syrian Kurdish YPG militia will be stripped of their weapons when withdrawing from the northern Syrian city of Manbij as part of a roadmap agreed with the United States, Turkish Foreign Minister Mevlut Cavusoglu said on Tuesday.
The northern Syrian city of Manbij is under the protection of the US-led coalition against Islamic State after an increase in "Turkish threats" against the city, a Kurdish-allied militia that controls the city said.
Turkish warplanes and artillery struck targets held by the Kurdish YPG militia in north Syria on Sunday, security sources said, as Turkey pressed on with a cross-border campaign launched last week with its Syrian rebel allies.
The United States has made it clear to Syrian Kurdish forces that they must return to east of the Euphrates river after seizing control of the Syrian town of Manbij to retain US support, Vice President Joe Biden said on Wednesday.
US-backed forces trying to oust Islamic State militants from the Syrian city of Manbij took "almost complete control" of the city on Saturday, the Syrian Observatory for Human Rights said.
A US-backed force fighting to drive Islamic State out of Manbij said on Thursday it was giving the jihadist group 48 hours to pull out of the surrounded northern Syrian city.