The US has reportedly dropped weapons to rebel fighters in Syria as the UN Security Council considers dropping food and medicine by air to civilians, Al Jazeera reported.
Witnesses say the US delivered the weapons to armed units battling the Islamic State (IS) group in Syria.
The developments come as a former Russian diplomat tells Al Jazeera that his country is seriously considering putting boots on the ground in Syria.
The weapons supplies were airdropped to rebels in Marea, a town in the northern province of Aleppo, on Friday, the Syrian Observatory for Human Rights (SOHR) said.
"Coalition airplanes dropped ... ammunitions, light weapons and anti-tank weapons to rebels in Marea," Rami Abdel Rahman, the SOHR head, said.
He said it was the first time the coalition had made such a drop to rebel fighters other than the Kurds.
A US defense official confirmed that the airdrop took place but denied that they included light weapons or anti-tank weapons.
In recent days, fighting has intensified near Marea, with the UN sounding a warning over the fate of an estimated 8,000 Syrians trapped by the violence.