BAGHDAD, Aug 6 (Reuters) - Four U.S. soldiers died on Monday in an explosion while on combat duty in Diyala province in Iraq, the U.S. military said. Twelve other soldiers were wounded in the attack in a volatile region of the country where American forces have launched a major operation to combat insurgents. Diyala has seen a spike in violence since a security crackdown in Baghdad forced insurgents and Sunni Islamist al Qaeda fighters into surrounding areas.
