On Wednesday, Russia carried out airstrikes at the al-Tanf garrison, near Syria’s border with Jordan in southeast Syria, Wall Street Journal reported. 

Russia notified the US through a communications line set up years ago that it was conducting the airstrikes in response to an attack against Syrian government forces.

Soon after, Russian jet fighters, including two Su-35s and one Su-24, were observed traversing the area over al-Tanf before striking a combat outpost at the garrison, a US military official said.

The advance notice of the strike was suggested to US officials.

The media reported on Thursday that unidentified drones targeted the headquarters of the terrorist group "Maghawir al-Thawra" inside the US base "al-Tanf", which is one of the most important centers of the US forces in Syria, on Wednesday night.

The US Pentagon officials told CNN that the attack was carried out by Russia and that Russia had warned Washington to pull out its forces before attacking them.