By Sholnn Freeman and Zaid Sabah
Washington Post Staff Writers
Friday, May 9, 2008 9:00 AM

BAGHDAD, May 9 -- A U.S. military spokesman said a man detained Thursday in northern Iraq is not wanted terrorist Abu Hamza al-Muhajer, the leader of the Sunni insurgent group al-Qaeda in Iraq.

"It's not him," the military spokesman said.

Iraqi police announced early Friday that Muhajer had been found sleeping during a midnight raid of a house in the northern city of Mosul and had confessed his identity in an interrogation -- a development that would have been a significant coup for Iraqi security forces.

The U.S. military spokesman, however, said there was apparently confusion because the man who was captured has a similar name.

Muhajer -- whom the Iraqis also reported had been killed in May, 2007 -- is believed to be an Egyptian, about 40 years old and an associate of Osama bin Laden's deputy, Ayman al-Zawahiri. He is believed to have taken over the leadership of al-Qaeda in Iraq after the death of Abu Musab al-Zarqawi in a U.S. airstrike in June 2006.

Since Zarqawi's death, the organization has continued a campaign of killing while pushing its strict interpretation of Islam.

In recent weeks, suicide bombers acting in a manner consistent with previous al-Qaeda in Iraq attackers have struck funerals, wedding parties and police and military checkpoints. The attacks chiefly target Sunnis who have joined forces with the U.S. military. In other developments, militia leaders loyal to Shiite cleric Moqtada al-Sadr on Thursday vowed to resist efforts by Iraqi and U.S. forces to relocate residents of some of the most violent parts of Baghdad's Sadr City neighborhood to camps.

For a month, the densely populated Shiite enclave on the capital's eastern edge has served as a battleground in clashes between Sadr's Mahdi Army militia and the joint fighting force drawn from the U.S. military and Iraqi security agencies. The battles have generally been taking place in the southwestern quadrant of the rectangular district, an area believed to be the launching site of most rockets targeting the heavily fortified Green Zone.

Abu Mustafa and Abu Bader, local Sadrist leaders and militia fighters, said Iraqi soldiers were telling people to leave Sadr City and go to tents set up at two nearby soccer stadiums. They also said soldiers had distributed leaflets telling residents in certain sectors to clear out. Abu Bader, who spoke on the condition he was identified only by his nickname, said people were resisting.

"We have tribal tradition," he said. "We are not going to send our families to stay in stadiums and soccer fields. There is no way we are going to put our people at the mercy of Americans and the Iraqi national guard."

Abu Bader cited American detention practices, and the Abu Ghraib prisoner abuse scandal in particular, as the source of people's fears.

Maj. Mark Cheadle, a U.S. military spokesman, denied knowledge of a campaign to remove residents from Sadr City. "We don't know anything about that," he said. "If they are doing it with loudspeakers, they are doing it quietly, because we are not hearing it."

Abu Mustafa reported "light clashes" with American and Iraqi forces Thursday, saying that patrols had been sent deeper into the district from multiple directions. The patrols turned back, he said, after being confronted by Mahdi Army fighters.

Abu Mustafa said American helicopters were also bombing houses in the area.

American and Iraqi commanders have said they are taking precautions to limit the impact on innocent civilians and property.

Also Thursday, fighters launched two rockets from Sadr City that struck a home in central Baghdad, killing two Iraqi civilians and wounding eight others, the U.S. military said.An Iraqi police official said at least four fighters and 22 other people were wounded in the district when militiamen clashed with Iraqi forces backed by U.S. helicopters.

In Salahuddin province, north of Baghdad, a suicide bomber killed Mulla Nadhum al-Aswadi, a leader of the U.S.-backed Sunni force known as the Awakening, who was traveling in a convoy with the police chief in the town of Duluiyah.

In Samarra, about 65 miles north of Baghdad, U.S. forces backing the Awakening fighters killed five senior members of al-Qaeda in Iraq in a pre-dawn offensive, according to Mohammed al-Nesani, a local Awakening leader.

Special correspondent Dlovan Brwari in Mosul contributed to this report.