The head of Zain Iraq, the country\'s biggest mobile phone company, has resigned and will be temporarily replaced by the company\'s chairman, Zain said in a statement on Wednesday. \"Zain Iraq ... today confirmed that Emad Makiya will step down as chief executive officer of Zain Iraq with immediate effect,\" it said, adding that Makiya will continue to function as an adviser to chairman and interim chief executive Mohammed Charchafchi. The statement did not specify why Makiya, who became chief executive in June 2010, resigned, while Makiya himself did not respond to AFP requests for comment. Zain Iraq is a branch of Kuwait\'s Zain Group, which owns mobile phone operators across the Middle East. The firm is Iraq\'s biggest mobile phone company by market share.