The images, which have yet to be independently verified, were published by the Telegram channel Directorate 4, a group which monitors the situation in Syria and Iraq.
They show what appears to be US troops speaking to militia and walking through populated areas in the Syrian region of Manbij.
The photos may be a signal to Turkish forces and pro-Turkish militants threatening Manbij amid Ankara's ongoing operation in northern Syria against Kurdish militias.
Earlier this week, Turkish media reported that the US was beefing up its military presence in the Manbij region, establishing two new bases and deploying about 300 troops, armored vehicles and construction units. Kurdish commanders speaking to Sputnik confirmed Friday that the US, France and the UK were beefing up their presence in Manbij, adding that this seemed to indicate that Washington and Ankara had not reached an agreement on each country's ongoing operations in the region.
The Syrian government has repeatedly voiced its opposition to the illegal operations of foreign armies on its sovereign territory. On Friday, Syrian UN Ambassador Bashar Jaafari reiterated Damascus's demand that Turkey withdraw from Afrin and indicated that the Syrian government had not received any official information regarding President Trump's plans to pull US troops out of the country. He also said that Syria would never agree to Israel's ongoing occupation of the Golan Heights.