Arab army chiefs of staff have drawn up a plan for a new Arab joint force to intervene in the Mideast to combat terrorism, amid differences between them on where to put the force’s headquarters. The plan, drafted Sunday by the army chiefs of staff in Cairo, says membership in the force is “voluntary” and it will be governed by defense ministers of member states. It says if only three countries sign up, it is enough to put the plan into action. However, there was dissention over the idea of the body convening in Egypt, the home of the Arab League. Officials say that idea was met with Qatari and Algerian objections. The officials spoke Sunday on condition of anonymity because they were not authorized to speak to journalists.