One man was killed when US troops in north-east Syria returned fire after their convoy came under attack near a checkpoint manned by forces loyal to Bashar al-Assad on Wednesday.

At one point in the standoff, a Russian army convoy also arrived at the scene in an apparent attempt to mediate the rare confrontation involving US and Syrian fighters.

A Pentagon spokesman said US-led coalition forces were conducting a patrol near the town of Qamishli when they encountered a checkpoint occupied by pro-government forces.

“After coalition troops issued a series of warnings and de-escalation attempts, the patrol came under small arms fire from unknown individuals,” said Col Myles Caggins, a spokesman for the US-led coalition.

“In self-defense, coalition troops returned fire,” he said.

One Syrian man was killed and another was wounded, according to Syrian state media.

A video posted on state news agency Sana’s website showed angry men firing small arms at a convoy of several armored US vehicles flying the US flag. Some residents pelted the convoy with stones, while another dumped a bucket full of dirt on the back of one vehicle.

Photographs and video from the scene showed armored vehicles with US, Russian and Syrian flags next to each other. One vehicle was stuck in the dirt, apparently having veered into a ditch, while another had a flat tire.

In one video, a resident walked up to US soldiers at one of the vehicles, holding a US flag, screaming: “What do you want from our country? What is your business here?”

Replying in English, a soldier tells the shouting man to “back off!”

The Syrian Observatory for Human Rights said residents and armed pro-government militiamen blocked the path of a US convoy. The militia fired in the air, prompting the American troops to fire smoke bombs.

The Observatory, which has a network of activists on the ground, said it was not clear if the person killed was a civilian or a militia member.

“The situation was de-escalated and is under investigation,” said Caggins in a statement. Air Force Lt Col Carla Gleason, traveling with the US defense secretary in Brussels, said no Americans were killed in the incident.

The Russian defence ministry said later that “a conflict took place between US troops and the local population” leaving one resident dead and another wounded.

It said that the arrival of Russian troops at the scene had made it “possible to prevent further escalation of the conflict”.

Hundreds of US troops are stationed in north-eastern Syria, working with the Kurdish-led Syrian Democratic Forces to fight against Isis.