Baghdad, Iraq ? Tensions continued to rise Friday between American forces and the Mahdi Army, whose leader, Shiite cleric Muqtada al-Sadr, is one of Prime Minister Nouri al-Maliki’s strongest backers.

U.S. and Iraqi troops have raided nine al-Sadr offices since an American soldier was reported missing and possibly kidnapped Tuesday, al-Sadr supporters said.

The raids and a blockade of the Baghdad neighborhood and al-Sadr stronghold of Sadr City have so angered Sadrist leaders that some said Friday there already would have been large-scale attacks on U.S. troops if al-Sadr hadn’t held his forces in check.

American military officials are withholding the missing soldier’s name to protect his family members in Baghdad. Family members have told U.S. officials that the soldier, an American of Iraqi descent, was visiting them in central Baghdad when three carloads of masked gunmen seized him. The kidnappers later phoned the family.