The United States has carried out air strikes on positions of so-called Islamic State (IS) in Libya, following a request by the UN-backed government there, the Pentagon says.
The strikes targeted positions in the port city of Sirte, an IS stronghold.
Libyan PM Fayez Sarraj, in a televised address, said the strikes caused "heavy losses".
Western powers have become increasingly concerned at IS's growing presence in Libya.
The air strikes are the first such US military intervention co-ordinated with the Libyan unity government.
There have been two previous US attacks on IS targets in Libya - last February and in November.