The United States has launched a campaign of airstrikes against Islamic State in Libya, its first military intervention against the group in its stronghold of Sirte.
Strikes were authorised by President Barack Obama after being requested by the United Nations-backed government in Libya, which has been fiercely battling for Sirte for three months.
Islamic State of Iraq and the Levant (Isil) holds several strategically important sites in Sirte, including the university, the main hospital and the Ouagadougou conference centre, where it is believed to have stockpiled large amounts of ammunition.
A Pentagon spokesman said an Isil tank and other vehicles were targeted with "precision strikes" and there would be more to come. He said no ground troops would be deployed.
The spokesman said: "Additional US strikes will continue to target Isil in Sirte to enable the Government of National Accord to make a decisive, strategic advance."
Prime Minister Fayez Serraj, speaking on Libyan television, said: "The first air strikes were carried out at specific locations in Sirte today, causing severe losses to enemy ranks."
Forces aligned with the government have been battling Isil in Sirte, on the Mediterranean in northern Libya, since May. The air strikes came amid fears about Isil's increased threat to Europe.
Mr Obama authorised them following recommendations from Ash Carter, the US Defence Secretary, and General Joseph Dunford, the chairman of the Joint Chiefs of Staff.
Earlier this year US forces estimated Isil was up to 6,000-strong in Libya, including some who moved from Syria, though numbers have likely fallen.