Arab leaders at a summit in Egypt announced the formation of a unified military force to counter growing security threats from Yemen to Libya, and as regional heavyweights Saudi Arabia and Iran engage in sectarian proxy wars.

Working out the mechanism and logistics of the unified force, an idea floated by Egyptian President Abdel Fattah al-Sisi, could take months.

Previous, similar schemes have failed to produce tangible results in the divided Arab world. Egyptian Foreign Minister Sameh Shukri told a news conference the Arab force would be voluntary, meaning no one country would be forced to take part and it could give member states flexibility should differences arise. At least two countries have committed to the force, he added. […]