(Adds details on al Qaeda leader's involvement) MOSUL, Iraq, March 6 (Reuters) - Dozens of al Qaeda-led militants stormed an Iraqi jail in the northern city of Mosul on Tuesday and freed up to 140 prisoners in one of the biggest prison breaks since the U.S.-led invasion in 2003, police said. As many as 300 militants led by Abu Omar al-Baghdadi, leader of the self-styled Islamic State in Iraq, attacked Mosul's northwestern Badoush prison just after sunset in the ethnically mixed city and overwhelmed police, who were forced to call the U.S. military for backup, officials said. Hisham al-Hamdani, a member of the Mosul provincial government, said Abu Omar al-Baghdadi took part in the attack himself. The Islamic State in Iraq is a body set up by al Qaeda's Iraq wing and other Sunni militant groups in October. Most of the prisoners were believed to be insurgents, police said. It was unclear if there were any clashes between gunmen and police during the incident. Saddam Hussein's nephew, Ayham Sabawi, escaped the same prison in December after he was accused of financing the Sunni insurgency against U.S. forces and the Shi'ite-led government.
