Police left the building when the militiamen, loyal to anti-American cleric Muqtada al-Sadr, arrived. The militia was still controlling the facility as of late afternoon.
The British military had maintained a small number of soldiers at the command center to help train Iraqi police.
However, the British withdrew Saturday night "in the framework of the plan for the handover" of British positions in the city to Iraqi control, said British spokesman Maj. Matthew Bird.
Basra, Iraq's second largest city and a major oil hub, has seen frequent violence between Shiite militias vying for power, including assassinations of Iraqis and frequent attacks on British bases around the city.
Britain has withdrawn hundreds of troops from Iraq, leaving a force of around 5,500 based mainly on the fringes of Basra, 340 miles southeast of Baghdad.
Last Wednesday, former U.S. Army Gen. Jack Keane, who was vice chief of staff at the time the Iraq war was launched in 2003, said Britain has allowed deteriorating security in southern Iraq to get worse.
He warned that American troops may need to plug the gaps if Prime Minister Gordon Brown withdraws significant numbers of British soldiers.
U.S. Air Strike Kills Four Kurdish Policemen
A U.S. helicopter attacked two Kurdish police outposts Sunday, killing four policemen and wounding eight others, a Kurdish security official said. The U.S. military said it was investigating the report.
Jabar Yawer, spokesman for the Kurdish Peshmerga militia, said the attack occurred about 10 a.m. on two small police outposts on a road linking Qara Tepe and Sadiya, about 65 miles northeast of Baghdad. He said two police vehicles also were destroyed and he believed the attack was mistaken friendly fire.
He said the two posts were established about 700 yards apart along the road after al-Qaeda fighters killed a group of university students traveling the stretch of highway in June 2006.
Karwan Ghafour, a 26-year-old policeman wounded in the attack, said he did not know what could have provoked the air strike.
Yawer said police from the posts that were hit had launched a joint operation two days ago with U.S. forces and had killed a militant fighter.
Lt. Col. Christopher Garver, a U.S. military spokesman, said he had only partial information about an incident in that area.
"We have reports that there were two vehicles that were destroyed in the engagement by a helicopter strike," Garver said, adding that he was unable to be certain the two incidents were the same.
Iraq Officials Say Civilians In House Bombed By U.S. Military
The U.S. military said it dropped a precision bomb on a house in Samarra after 12 men who fought U.S. troops escaped into the structure. City police and hospital officials said seven civilians, including five children, were killed.
Lt. Col. Michael Donnelly, spokesman for U.S. forces north of Baghdad, said a gunfight broke out when the 12 men ran into a house where U.S. troops were conducting surveillance. The 12 opened fire on the Americans, then escaped in a truck and were tracked by an unmanned drone above the city. They were seen darting into the house that was subsequently bombed.
Officials in the Samarra Joint Coordination Center and the hospital there said Mohammed Abdul Wahab, his wife and five of their children ages 4- to 8-years-old were killed. The officials, who refused to be named fearing retribution, said five other people were wounded, including three children, ages 4 to 10.
"We cannot confirm those numbers, but can confirm the 12 or so attackers went into this house following an attack on our soldiers, who were trying to bring about some level of peace to the people there," Donnelly said in an e-mail response to a question about the attack.
Maliki Slams U.S. Senators, France For Criticism
Iraq's beleaguered prime minister on Sunday lashed out at American critics who have called for his ouster, saying Sens. Hillary Rodham Clinton and Carl Levin need to "come to their senses."
Nouri al-Maliki, who is fighting to hold his government together, issued a series of stinging ripostes against a variety of foreign officials who recently have spoken negatively about his leadership. But those directed at Democrats Clinton, of New York, and Levin, of Michigan, were the most strident.
"There are American officials who consider Iraq as if it were one of their villages, for example Hillary Clinton and Carl Levin. They should come to their senses," al-Maliki said at a news conference.
Al-Maliki launched the verbal counteroffensive in the final days before the American commander in Iraq, Gen. David Petraeus, and U.S. Ambassador Ryan Crocker are due in Washington to report to Congress on progress in Iraq since the introduction of 30,000 more America troops.
The Shiite prime minister said a negative report by Petraeus would not cause him to change course, although he said he expected that the U.S. general would "be supportive of the government and will disappoint the politicians who are relying on it" to be negative.
Al-Maliki appeared stung by the recent series of critical statements about his government, including one from President Bush, who said he was frustrated that al-Maliki had failed to make progress on political benchmarks. Crocker has said the lack of movement had been "highly disappointing."
And most recently Sen. John Warner, R-Va., said the United States should order a token withdrawal of forces by Christmas. The former chairman of the Armed Services Committee said such a move would show al-Maliki that Washington was serious about progress on reconciliation among the country's religious sects and ethnic groups.
Warner and Levin traveled to Iraq together earlier this month as part of the multitude of Congressional delegations who are visiting the country before the expected heated debate on Capitol Hill about U.S. troop levels and plans for a withdrawal.
Al-Maliki also criticized some U.S. military actions.
"Concerning American raids on Shula (a northern Shiite neighborhood) and Sadr City (the Shiite slum enclave in east Baghdad). There were big mistakes committed in these operations. The terrorist himself should be targeted not his family.
"When they want to detain one person, they should not kill 10 others. These are mistakes which we have to deal with. We will not allow the detaining of innocent people. Only the criminals should be detained," the angry al-Maliki declared.
Two nights ago the U.S. military raided the Shula neighborhood and said it killed eight "terrorists" who had attacked an American patrol from rooftops. Some Iraqis reported many civilians were killed and wounded.
U.S. forces also are routinely raiding Sadr City, often calling in helicopter fire. The U.S. says it targets only Shiite militia fighters. Iraqi officials regularly report civilians killed in the raids.
Maliki's comments were not solely directed to U.S. targets. He called on the
French government to apologize for comments reportedly by the country's foreign minister that the Iraqi leader should step down.
"We welcomed their foreign minister and we were happy with his visit, but they have to show us respect," al-Maliki told reporters. "We call upon the French government to apologize about this issue."
French Foreign Minister Bernard Kouchner visited Iraq this month in a highly symbolic gesture to the United States effort in Iraq after years of icy relations over the 2003 American-led invasion. Kouchner said Paris wanted to "turn the page" and look to the future.
However, in an interview with Newsweek magazine, Kouchner said he told U.S. Secretary of State Condoleezza Rice that al-Maliki has "got to be replaced."
"There's a lot of support for, for instance, (Vice President) Adil Abdul-Mahdi, who's an impressive fellow, and not only because he studied in France. He's solid. Of the people who are available, he's widely seen as the one that ought to have the job."
But Kouchner said it was uncertain whether al-Maliki would be replaced "because it seems President Bush is attached to Mr. Maliki. But the government is not functioning."