The BBC quoted US officials as saying on Saturday that the United States had sent six additional tanks and more than 100 troops to northeastern Syria.
US and Russian forces regularly patrol northeastern civil war-torn Syria. Tensions in the region have risen as the two forces have clashed several times this year.
A spokesman for the US Central Command said on Friday that the United States did not want to see a conflict with any other country in Syria. However, if necessary, the joint forces must be protected. ”
The U.S. official, speaking on condition of anonymity because he was not authorized to speak on condition of anonymity, said: Russia and other parties should refrain from any amateurish, unsafe and provocative activities there. ”
Citing U.S. officials, NBC News reported that new troops and armored vehicles had been sent to prevent the entry of Russian forces into a "safe zone" in northeastern Syria from which joint US and Kurdish forces operate.
Seven U.S. soldiers were wounded in the fighting when a group of U.S. troops collided with a Russian armored vehicle late last month. The video of the fight was later posted on social media Twitter.
The United States and Russia have blamed each other for the killings.
The United States has said Russian troops entered its "safe zone". But according to the agreement, they are not supposed to enter there.
Russia says it has already told US troops to patrol the area.
About 500 US troops are still stationed in northeastern Syria. They support Kurdish forces fighting Islamic State there.
Russian forces, on the other hand, are fighting for Syrian President Bashar al-Assad.
On October 7, 2019, US President Donald Trump announced the withdrawal of 1,000 troops from Syria. A few months later, he said he would keep some US troops in the country to protect Syria's oil wells.