Washington, Sep 13 (IANS) Retired American general John Allen is being tasked with coordinating a global coalition in support of US-led efforts to combat the Islamic State militant group running amok in Syria and Iraq, the State Department said Friday. The Retired Marine Corps four-star general was named as the special presidential envoy by Secretary of State John Kerry, who is in the Middle East trying to mobilise regional support for Washington's expanding battle against the radical group, Xinhua quoted State Department spokesperson Marie Harf as saying.