Iraqi police arrested dozens of members of Shi'ite cleric Moqtada Al Sadr's Mehdi Army militia on Saturday, hours after two policemen were killed in gunbattles in the southern city of Kut, police said.
Clashes this week between Iraqi security forces and the militia in Kut, 170km (105 miles) southeast of Baghdad, have raised fears a ceasefire called by Sadr may unravel, although the violence has so far been confined to Kut.
It is the first major violation of the seven-month-old truce, which has been credited by the US military with helping to reduce violence between majority Shi'ite and Sunni Muslims that has killed tens of thousands of Iraqis.
Sadr clarified the conditions of the truce last week, telling followers they could defend themselves if attacked, an apparent response to complaints among his fighters that US and Iraqi forces were exploiting the ceasefire to target them.
"This operation started in the early morning and so far we have arrested 25 wanted people from the Mehdi Army," said Lieutenant Aziz Al Amara, who commands a rapid reaction unit.
Another police official, who declined to be named, said 70 people had been detained. There was a heavy presence of Iraqi and US forces in the city. US military spokesmen have given few details about their involvement in the clashes.
Police say at least 13 people have been killed in fighting since Tuesday.
Separately, the US military said eight Iraqi civilians were wounded when a barrage of 29 Katyusha rockets hit a neighbourhood near a US embassy regional office in Hilla, 100km (60 miles) south of Baghdad, late on Friday.
Three houses and a school were damaged and another nine unlaunched rockets were found by Iraqi security forces.
Hilla police chief Brigadier-General Fadhil Al Sultani blamed an unspecified militia for the attack and said a suspect had been detained.
The latest outbreak of violence in Kut began on Friday night when police tried to enter two neighbourhoods where there is a strong Mehdi Army presence. Clashes erupted and residents reported the sound of gunfire and explosions.
Amara said two policemen were killed and eight wounded on Friday, six of whom were in a serious condition and had to be transferred to the local US military base for treatment.
A US military spokeswoman said US forces were aware of three policemen being wounded in fighting involving small arms fire and rocket-propelled grenades.
A mortar attack early on Saturday wounded six people, including three members of the same family, Kut police said.
Sadrists have sought to distance themselves from the fighting. Luwaa Sumaisem, a senior aide to Sadr, denied members of the Mehdi Army were involved in Friday night's clashes.
"Mehdi Army didn't intervene in the clashes and everyone in their houses are following the order of Moqtada Al Sadr," he told Reuters in the holy Shi'ite city of Najaf.
The fighting in Kut comes amid an increase in attacks in Iraq since January, although overall levels of violence are down since last year.
The United Nations released its Human Rights Report on Iraq on Saturday covering the six months to December 31.
It said there had been a marked decrease in violent attacks in the last three months of 2007. But several large bombings in the past two months have been blamed on Al Qaeda by the US military and Iraqi government.
UN envoy Staffan de Mistura said those blasts had failed to trigger the kind of deadly sectarian reprisals that followed the 2006 bombing of a Shi'ite shrine in Samarra.
"There is a feeling among Iraqis of tiredness, that violence has produced nothing but violence," de Mistura said. (Reuters)
Police arrest dozens after clashes in Iraqi city