A US 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 air-strike 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 Moqtada A-Sadr ordered his Mahdi Army fighters to stand down. Prime Minister Nuri 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 suicide 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 US military confirmed the attack but put the casualty toll at five dead and 19 wounded. Nobody claimed responsibility for the bombing. But Mosul, 360 kilometers (225 miles) northwest of Baghdad, is believed to be the last major urban center where Al-Qaeda in Iraq maintains a substantial presence. The US-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 US spokesman, said no civilian casualties were reported in that attack, but the military was looking into reports that civilians were killed in a second air-strike. 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, US 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 air-strikes had been conducted over the last 24 hours in Basra to support the Iraqis in the fight. __