USA military spokesman Myles Caggins said American-led coalition forces were conducting a patrol of eight vehicles near Qamishli and encountered a checkpoint occupied by pro-Syrian militia forces.
Earlier, Syrian and Turkish media said one person was killed in the shooting at the checkpoint and that USA warplanes had carried out at least one air strike subsequently.
One man was killed when United States 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.
The U.S. and Russia have for years worked to deconflict their operations in the country, but a top American diplomat has warned of increased complexity in northeastern Syria, where U.S. troops are deployed and have had "minor dustups" with Russian patrols.
"The situation was de-escalated and is under investigation", said Caggins in a statement.
Photographs and video from the scene showed armored vehicles with US, Russian and Syrian flags next to each other.
A cellphone video, showing an American armored vehicle being blocked by a civilian vehicle, was broadcasted by Syrian state-run Al-Ikhbariya television.
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. Air Force Lt Col Carla Gleason, traveling with the USA defense secretary in Brussels, said no Americans were killed in the incident. Russian Federation has supported President Bashar al-Assad's government, while Turkey is the rebels' main backer.
FILE- Russian forces patrol near the city of Qamishli north Syria Oct. 24 2019
Syrian and Turkish media claimed one person was killed in the shooting at the checkpoint and that US warplanes had subsequently carried out at least one airstrike.
The Observatory, which has a network of activists on the ground, said it is not clear if the killed was a civilian or a militia member.
While U.S. officials did not immediately provide specific details on the circumstances leading to the incident, Syria's state news agencies and humanitarian groups offered reports. The Observatory also said a Russian convoy arrived on the scene to defuse the tension.
It comes after the U.S. Department of Defense announced that 109 American troops were diagnosed with mild brain injuries following the Iranian missile strike on Iraqi bases last month.
Since then, Russian forces and the Syrian government have entered the border region between Turkey and northeast Syria with the aim of filling the area evacuated by US forces.
Turkish President Recep Tayyip Erdogan addresses his ruling party members at parliament in Ankara on Wednesday. He said Turkey is determined to force the Syrian military back from the gains it has made in Idlib, giving Syrian troops until the end of February to retreat.
Erdogan was referring to the 2018 agreement between Russian Federation and Turkey in which the two countries' troops would enforce a demilitarized zone in Idlib. Several of these posts have been surrounded by government forces in recent weeks. "It's inadmissible and it runs contrary to the Sochi agreements", Peskov said in a conference call with reporters.