The Libyan branches of Islamic State (ISIS), al-Qaeda and the Muslim Brotherhood are finalising a "mega merger'' that would include the formation of a joint council of sages, according to London-based newspaper Al Sharq al Awsat.

Citing leaked documents, the paper said the Islamist organisations are considering an alliance, which comes on the heels of an international effort to unite Libya's various factions and warring militias under one government, the Arabic language daily reported, according to WND.

"The three terror groups want to send a message that 'all the Islamist opposition elements speak in one voice and should be treated as such,'' a source told the Arabic newspaper, according to Breitbart.

Negotiations among the three Islamic groups were reportedly prompted by reports of "a rapprochement between the internationally recognised government based in Tobruk and the unrecognised government in the capital Tripoli."

According to the paper, the Muslim Brotherhood is considering a united Islamic front even though the movement is officially in favour of forming a unity government. But sources within the movement told the paper that their support for the international endeavour is merely tactical, and that they're waiting for it to collapse, Breitbart reported.

The parties have agreed to form a joint Shura (advisory) council and territories that are currently under Islamic control will be divided among them, said the report.

An al-Qaeda representative was quoted as saying that the move would inspire Islamist in Algeria and Egypt to follow suit.

Moreover, Breitbart Jerusalem also disclosed of mediation efforts between the Muslim Brotherhood-aligned Hamas and Salafists aligned with the ISIS.

A previous report by the paper indicated that Shadi al-Menai, one of the leaders of Wilayat Sinai, the ISIS branch in Sinai, visited Gaza in a bid to mediate between Hamas and local Salafi groups after clashes erupted that resulted in the arrests of dozens of jihadists by Hamas forces.