US and British forces battled Mehdi Army fighters in Baghdad and the southern city of Basra after their leader, Shia cleric Moqtada al-Sadr, made a rare public appearance and called on US troops to get out of Iraq.
Five gunmen were killed in an air strike during a pre-dawn raid on Saturday in the cleric's Sadr City stronghold in Baghdad, the US military said. A militant leader suspected of ties to Iran's Revolutionary Guards was captured.
In the southern oil hub of Basra, the British military said "a number" of militia fighters were killed in an air strike overnight after they attacked British troops with rocket-propelled grenades, mortars and machineguns.
The attacks were believed to be in retaliation for the killing of the top Mehdi Army commander in the city on Friday by British-backed Iraqi special forces, the British military said in a statement.
A Reuters reporter saw eight coffins at a funeral for those killed in Basra. A hospital official said 22 others had been wounded. Residents said a helicopter had attacked a group of civilians protesting against the death of the Mehdi Army leader.
The fighting came a day after Sadr appeared in public for the first time in months and repeated his demand for a timetable for US troop withdrawal. US officials say he has been in hiding in Iran, but his aides say he never left Iraq.
Some analysts have speculated that Sadr had come back to reassert his authority over his militia, which the US military says has begun fragmenting into rogue splinter groups. In Basra, the British military described the situation as calm but tense on Saturday after overnight fighting.