US troops mounted two raids against Iraqi Shia forces in Baghdad on Sunday, killing up to 20 gunmen in a raid on a mosque, and arresting more than 40 interior ministry personnel guarding a secret prison.
Details were sketchy but the two operations looked like US strikes against sectarian Shia militias of the kind the US ambassador said on Saturday must be eliminated if Iraq is to form a unity government and halt a slide toward civil war.
The US military made no immediate official comment and a senior interior ministry official denied the arrests of its personnel at a facility in central Baghdad where government and political sources said US troops freed 17 foreign prisoners.
But a US source confirmed that American and Iraqi forces had detained 41 interior ministry personnel guarding a secret bunker complex. Most foreigners in detention are accused of being al Qaeda fighters who come to Iraq to fight Americans.
Iraqi police and residents said a US raid on a mosque in the Shaab district of east Baghdad sparked fierce clashes with militiamen of the Mehdi Army loyal to cleric Moqtada al-Sadr. A medical source at Yarmouk hospital said he saw 18 bodies of Iraqis killed in the operation.