Countdown begins to capture IS' Libyan stronghold of Sirte

Libya's unity government loyalist forces have announced  the beginning of the countdown to liberate the Islamic State group stronghold of Sirte.

Commanders of the military operation al-Bunyan al-Marsous are holding intensive meetings to prepare for the final battle to "uproot" the extremist group from the coastal city, the pro-government forces said in a statement published by Anadolu news agency.

"International forces supporting al-Bunyan al-Marsous launched four airstrikes on Saturday night targeting IS sites in the city," the statement read.

On Monday, US airstrikes struck IS positions in Sirte for the first time in response to a request from the Tripoli-based Government of National Accord [GNA].

The bombings were authorised by US President Barack Obama after recommendations from top Pentagon officials, Pentagon press secretary Peter Cook said at the time.

Libyan Prime Minister Fayez al-Sarraj has said in a televised speech that the American involvement would be "limited in time and will not go beyond Sirte and its suburbs".

The fall of Sirte, located 450 kilometres [280 miles] east of Tripoli, would be a major blow to IS, which has faced a series of setbacks in Syria and Iraq.

The Tripoli-based government launched operation al-Bunyan al-Marsous in May to retake Sirte, which the extremists have controlled since June 2015.

More than 300 pro-GNA fighters have been killed and over 1,500 wounded since the beginning of the battle for Sirte, according to medical sources in Misrata.

Government forces entered Sirte on 9 June, reaching central and northern parts of the city. IS has hit back with suicide car bombs and sniper fire.

Pro-GNA forces are mostly made up of militias from western Libya established during the 2011 revolt that overthrew long-time dictator Muammar Gaddafi.

Libya has since descended into chaos, with rival authorities vying for control in the oil-rich country.

The GNA was the result of a UN-brokered power-sharing agreement struck in December, but it has yet to be endorsed by the elected parliament based in the country's far east.