Russian and Assad regime troops surround a US military convoy near Qamishli, Syria, February 2020 (AP)

US troops have clashed with an Assad regime unit in northeast Syria.

One regime soldier was reportedly killed and two wounded. No US personnel were injured, said Central Command spokesman Col. Myles Caggins.

Coggins said a convoy of US personnel and Kurdish-led Syrian Democratic Forces were fired upon near the city of Qamishli in Hasakah Province.

Coalition and Syrian Democratic Forces, conducting a routine anti-ISIS security patrol near Tal Al-Zahab, Syria, encountered a checkpoint occupied by pro-Syrian regime forces.

After receiving safe passage from the pro-regime forces, the patrol came under small arms fire from individuals in the vicinity of the checkpoint. Coalition troops returned fire in self-defense.

The spokesman said American helicopters were overhead on escort duty but did not carry out airstrikes. He said the US military had not confirmed regime casualties or the attackers as uniformed regime troops.

The regime’s SANA news agency, citing a “military source”, claimed the US patrol “opened several rounds of fire” when it was prevented from passing the checkpoint. The official maintained that the regime casualties occurred when “after about 30 minutes, two US warplanes attacked the army personnel at the checkpoint with heavy machine guns”.

A pro-opposition analyst identified the slain soldier as a member of the regime’s 54th Regiment.

Kurdish authorities, with the US-backed SDF, have controlled much of northeast Syria since removing the Islamic State between 2017 and 2019. However, the Assad regime, supported by Russia, occupied part of the area as ISIS was defeated.

Convoys have regularly passed through checkpoints with few clashes. But in February, one man was killed and another injured in an incident, also near Qamishli, with Russian and Assad regime troops surrounding a US convoy.