The Wall Street Journal quoted US military personnel as saying that Russian attacks this week targeted the Al-Tanf base of the international coalition in Syria.
The US military said that this month, the Russian forces carried out operations against the international coalition in Syria, including targeting two Sukhoi fighters at the Al-Tanf base this week.
The sources added that Russia had notified the United States before the bombing that it would respond to an alleged attack against the regime forces.
According to these sources, Russia's attacks raised Washington's concern that it could lead to a US-Russian confrontation in Syria.