BEIRUT—Syrian warplanes took off from an air base which was hit by US cruise missiles on Friday, and carried out air strikes on rebel-held areas in the eastern Homs countryside, the Syrian Observatory for Human Rights said.

The US Navy had fired dozens of missiles at the air base near Homs city in response to a chemical attack this week which Washington and its allies blamed on the Damascus government.

The British-based Observatory, a group monitoring the Syrian war using sources on the ground, said eight people had been killed in the US attack.

The extent of the damage to the Shayrat air base was not entirely clear, but the Syrian warplanes had "done the impossible" in order to continue using it for sorties, the Observatory told Reuters.