The British army's special unit the SAS has been deployed in Libya to pave the way for an international offensive aiming to halt the advance of the Islamic State (Isis) in North Africa. A coalition offensive of 6,000 European and US soldiers including 1,000 British troops will head to the war-torn nation to take part in a number of offensives against the militants.

Isis is desperate to assert more control in Libya because the oil-rich land could provide millions of dollars in revenue to fund terror attacks and to counterbalance the loss of territory in Syria and Iraq. In the past week militants in oil town of Ajdabiya have sworn allegiance to the Islamist group.

They were preceded by extremists in Misrata who swore allegiance to Isis-leader Abu Bakr al-Baghdadi. The group has a strong presence in the coastal city of Sirte roughly 250 miles from a huge oil refinery at Marsa al Brega.

Currently the UK is strategically bombing Daesh targets in Syria and Libya with 10 Tornados and six Typhoons stationed in the Mediterranean at RAF Akrotiri. A Royal Navy destroyer has been dispatched to the north African coast and the RAF has the capability to mount attacks in days.

A senior military source told The Mirror: "This Coalition will provide a wide range of resources from surveillance, to strike operations against Islamic State who have made significant progress in Libya. We have an advance force on the ground who will make an assessment of the situation and identify where attacks should be made and highlight the threats to our forces".

The SAS is planning to assist Libyan commanders on "battlespace management" and will pass intelligence to the Chief of Joint Operations, Lieutenant General John Lorimer. Last month a senior Isis commander in Libya named as Abu Nabil, who was also known as Wissam Najm Abd Zubaydi, was killed in a US air strike. Also, a red warning was issued for the nation's ancient treasures over threat of Daesh destruction.

The Libyan interior ministry has reported that around 5,000 Islamist militants are fighting in the country which is still gripped by civil war, despite representatives of Libya's two competing parliaments signing an agreement to end the country's civil war on 17 December.

The UN confirmed reports from intelligence agencies that Libya has become Isis's fallback position, turning the country into a "back-up" caliphate.