Russian forces have mediated an armed conflict between pro-regime and U.S. troops in northeastern Syria, the Russian military said Wednesday following a deadly incident.

U.S. soldiers killed one person in Syria’s Hasakah region after their vehicles were stopped at a checkpoint, according to Syrian and Turkish media. The shooting was reportedly followed by U.S. airstrikes on a village in rural Qamishli near the Turkish border.

The Russian military in Syria said the clashes erupted because the U.S. convoy “deviated from its route.” It identified the victim as a 14-year-old civilian.

“Further escalation of the conflict was prevented thanks only to the efforts of Russian servicemen who arrived at the scene,” the military said in a daily bulletin.

The U.S.-led coalition in Syria said its patrol troops “returned fire” after coming “under small arms fire from unknown individuals” at the pro-Syrian regime checkpoint. It later said a U.S. soldier suffered a “minor superficial scratch” in the incident.

The U.S.-Syrian clashes follow a series of standoffs between U.S. and Russian troops in Syria in recent weeks. America’s special envoy for Syria has accused Russia of violating the terms of de-confliction in what he characterized as an attempt to challenge the U.S. presence there.

Russia, a staunch ally of the Syrian government, launched a military air campaign in Syria in 2015 to help Damascus recapture parts of the country from rebels.

Moscow has long insisted that the U.S. military presence in Syria is illegal.

Reuters contributed reporting to this article.