US launches strikes on Islamic State in Libya's Sirte

US airstrikes struck Islamic State positions in the Libyan city of Sirte for the first time on Monday, the country's unity government head announced. The US Department of Defence later confirmed.

US military planes launched air raids in response to a request from the unity government, the Pentagon said.

"At the request of the Libyan Government of National Accord, the United States military conducted precision airstrikes against ISIL targets in Sirte, Libya, to support GNA-affiliated forces seeking to defeat ISIL in its primary stronghold in Libya," Pentagon press secretary Peter Cook said, using another acronym for IS.

The Libyan prime minister first announced the raids in a televised speech.

 "The first American air strikes on precise positions of the Daesh (IS) organisation were carried out today, causing heavy losses... in Sirte," Fayez al-Sarraj said.

The US strikes in Sirte were conducted in coordination with the military command centre of pro-GNA forces and "will continue", Cook said, but Sarraj said no foreign troops would be deployed into Libya.

"This has allowed our forces on the ground to take control of strategic positions," he said, adding that the American involvement would be "limited in time and will not go beyond Sirte and its suburbs".

"We asked for this support from the international community, notably the United States, but we want to point out that there will be no foreign presence on Libyan soil."

The bombings were authorised by US President Barack Obama after recommendations from top Pentagon officials

The bombings were authorised by US President Barack Obama after recommendations from top Pentagon officials, and the strikes are "consistent with our approach to combating ISIL by working with capable and motivated local forces", Cook added.

"The US stands with the international community in supporting the GNA as it strives to restore stability and security to Libya," he said.

A major operation was launched in May to recapture the IS-bastion of Sirte which has been under militant control since June 2015.

More than 280 pro-government fighters have so far been killed, medical sources suggest.

The coastal city is considered to be the militant group’s most important rear bases outside of Syria and Iraq and the country is said to boast 2,000 to 5,000 Islamic State fighters.

Agencies contributed to this report.