Arab states have said they will try to assemble a unified military force to combat common threats across the Middle East, as Yemen was described as being 'on the brink of the abyss' at the Arab League summit.

Leaders say the region is now more volatile and polarised than at any point in at least 35 years. The mooted force would be 40,000 strong, based in Cairo or Riyadh and would be deployed to counter threats anywhere from Libya to Yemen.

The concept, which is effectively a joint defence pact, was tabled by the Egyptian president, Abdel Fatah al-Sisi, at the summit in the Egyptian resort town of Sharm al-Sheikh, where all 22 members of the fractious body gathered on Sunday to discuss the myriad crises reverberating around the region.