A U.S. warplane destroyed a house in the southern city of Basra, killing a militant, the military said Thursday. Iraqi witnesses and hospital officials said at least three civilians were among the dead.
The American military said it was looking into reports that civilians were killed in a second airstrike in Basra but it could provide no further details.
The strikes in Basra underscored the high tensions as the Iraqi government continues a crackdown against Shiite militias four days after radical Shiite cleric Muqtada al-Sadr ordered his Mahdi Army fighters to stand down.
Prime Minister Nouri al-Maliki, meanwhile, said he plans to launch more security crackdowns like the one in Basra against "criminal gangs" in Baghdad and elsewhere in Iraq.
Speaking to reporters, he singled out Sadr City and Shula -- two Mahdi Army militia strongholds in Baghdad -- as likely targets in the future operations.
Al-Maliki did not mention by name the Mahdi Army militia, but said those areas are under the influence of "criminal gangs."
Baghdad also faced a series of bombings on Thursday, and the Iraqi military said a homicide car bomber attacked an Iraqi checkpoint west of Mosul late Wednesday, killing seven people, including a woman and a 5-year-old child, and wounding 12.
The U.S. military confirmed the attack but put the casualty toll at five dead and 19 wounded. Nobody claimed responsibility for the bombing. But Mosul, 225 miles northwest of Baghdad, is believed to be the last major urban center where Al Qaeda in Iraq maintains a substantial presence.
The U.S.-led coalition directed "aerial fires" against enemy forces fighting Iraqi troops Wednesday near the militia stronghold of Qibla in Basra, according to a statement.
The military later confirmed an American plane conducted the attack, saying one militant was killed.
Lt. Michael Street, a U.S. spokesman, said no civilian casualties were reported in that attack, but the military was looking into reports that civilians were killed in a second airstrike. He could not immediately provide further information.
Associated Press Television News showed cranes and rescue workers searching for survivors in the concrete rubble from the two-story house that was leveled.
Witnesses said three people were killed and three others believed to be buried in the rubble, apparently leading to confusion over the number of casualties.
"While we were preparing for evening prayer, U.S. aircraft bombed this house, we rushed to save survivals but in vain," a neighbor identified only as Haj Juwad told APTN. "The father, mother and a young boy were killed and three others were buried under rubble. We evacuated two people and one is still under the rubble."
Hospital officials said three bodies had been received, including two men and an elderly woman, and two women were wounded in the strike. The officials spoke on condition of anonymity because they weren't authorized to release the information.
The Qibla district where the attack occurred has seen some of the fiercest fighting in the offensive that began March 25 against criminal gangs that had wielded wide control in the country's oil capital and a major commercial center of 2 million people.
Despite an end to heavy fighting, the Interior Ministry spokesman, Maj. Gen. Abdul-Karim Khalaf, has said security operations were continuing and that an April 8 deadline for gunmen to surrender their weapons remains in effect.
British military spokesman Maj. Tom Holloway said a number of airstrikes had been conducted over the last 24 hours in Basra to support the Iraqis in the fight.
"We remain committed to supporting the government of Iraq ... and action will be taken against those who attack the Iraqis and coalition forces," he said.
In the wake of the fighting, Britain has suspended plans to withdraw 1,500 soldiers from southern Iraq.
The violence exploded March 25 when al-Maliki launched a major operation to wrest control of Basra from the militias, which had effectively ruled the city since 2005.
U.S. and Iraqi officials have maintained that the crackdown was directed at criminals and renegade militiamen but not the Sadrist political movement, which holds 30 of the 275 seats in the national parliament and is a major political force.
But the Sadrists believed the operation was aimed at weakening their movement before provincial elections this fall. The militia fighters mounted a fierce resistance, prompting the Iraqis to call in U.S. jets and British tanks and artillery to help in the battle.
The failure to gain a quick and decisive victory over the militias left al-Maliki politically battered, raising doubts about Iraqi military capability just a week before top U.S. commander Gen. David Petraeus briefs Congress about prospects for further American troop cuts.
In violence Thursday in Baghdad, a parked car bomb targeted a police patrol in western Baghdad, killing at least one civilian and wounding 10 other people, including three officers.
A roadside bomb struck an Iraqi army patrol in Baghdad's predominantly Sunni Yarmouk neighborhood, killing one soldier and wounding three others.
Three Iraqi civilians also were wounded in a U.S. airstrike targeting militants engaged in a gunbattle with U.S. ground forces near the southern Shiite city of Hillah, according to a military statement.
It said the U.S. troops then detained a Shiite militia leader accused of planning to assassinate local police officers and gathering intelligence for attacks in the southern city of Hillah. The incident was under investigation.
Iraqi police said four policemen and an armed night watchman for a store were killed and 11 other people were wounded, including two women, when U.S. troops opened fire after midnight in the center of Hillah.
The area has been the site of recent clashes between Iraqi security forces and Shiite militia fighters.