Russian Federation rejects allegation it bombed US-backed fighters in Syria

The reality of the frontline in Raqqa

The reality of the frontline in Raqqa

According to sources, the American "surrendered" and was first taken into custody by the Syrian Democratic Forces, a mostly Kurdish group working with the U.S.to fight ISIS on the ground.

"According to CNN, a USA military official told the outlet that the American citizen surrendered to the Kurdish elements of the Syrian Democratic Forces".

The decision to legally detain the man as a "known enemy combatant" comes as the Trump administration has been working to craft a detention policy, which could determine whether the US will resume sending detainees to the military prison at Guantanamo Bay, Cuba.

The call occurred after US -backed militias in Syria said they had come under attack on Saturday from Russian jets and Syrian government forces in Deir al-Zor province, a flashpoint in an increasingly complex battlefield.

The SDF, half of whose forces are members of the Kurdish People's Protection Units (YPG), are backed by the US-led Global Coalition to Defeat ISIS.

State Department spokesperson Heather Nauert also confirmed during a media briefing on Thursday evening that she had no further information on the individual's circumstances.

The deal angered the US military, which deployed drones to pick off ISIS fighters when they left the convoy to relieve themselves.

ISIS is a large movement which has attracted a lot of Western recruits, which has long fueled fear about what happens when they return home, particularly in the cases of those not caught, but who fled the battlefield. According to the New America think tank, 44 succeeded in reaching the Islamic State or other groups in Syria.

The Russian- and USA -backed campaigns against Islamic State in Syria have mostly stayed out of each other's way as the sides seek to avoid conflict, with the Euphrates often acting as a dividing line between the sides.

A federal jury convicted Khweis, 27, in June of providing and conspiring to provide material support or resources to Islamic State, and a related firearms count.

The strike occurred early Saturday, hitting an area east of the Euphrates River, near the city of Deir Ezzor.