BAGHDAD,(Reuters) – Iraq’s prime minister, in a very public demonstration of his influence over the U.S. military, announced the lifting on Tuesday of a week-old cordon around the Baghdad militia stronghold of one of his key Shi’ite allies.

Other checkpoints that have snarled traffic around the capital for the past week as U.S. and Iraqi forces have hunted a kidnapped American soldier would also have to open by 5 p.m. (1400 GMT), Prime Minister Nuri al-Maliki said in a statement.

U.S. spokesmen initially said they were unaware of the order distributed to the media and then said only that the military would try to “address concerns … about checkpoint operations”.

But a Maliki aide said the move, which follows days of public friction between the prime minister and U.S. officials in the run-up to next week’s U.S. congressional election, had been agreed with the U.S. ambassador and the U.S. military commander.

Reporters saw U.S. troops leave positions around Sadr City, the sprawling slum controlled by the Mehdi Army militia of anti-American Shi’ite cleric Moqtada al-Sadr, and Iraqi forces manning others open them up to let all traffic flow freely.

A crowd gathered outside the local headquarters of Sadr’s organisation, some firing in the air in celebration at the end of what a senior follower called a “barbaric and savage siege”.

Maliki and U.S. officials have been at odds for the past week ahead of Nov. 7 elections that could cost U.S. President George W. Bush’s Republicans control of Congress.

In the latest bout of mayhem in Iraq, police said more than 40 people were missing after a mass kidnap attack on minibuses travelling to Baghdad from the north.

In the city itself, police said a car bomb blasted a convoy of vehicles from a wedding party, killing up to 10 people, an Interior Ministry source said.

Maliki has rejected U.S. pressure to set a timetable for disbanding militias led by fellow Shi’ite Islamists and has demanded a freer hand to command the new Iraqi armed forces.

“The Commander in Chief, Prime Minister Nuri al-Maliki, has ordered the lifting of all barriers and checkpoints to open roads and ease traffic in Sadr City and other districts of Baghdad,” a statement from Maliki’s office said.

“Coalition forces have seen the order,” the main U.S. spokesman Lieutenant Colonel Christopher Garver said. “Our commanders are determining how coalition forces can best address the prime minister’s concerns about checkpoint operations.”

Sadr’s organisation, blamed by minority Sunnis for sectarian death squad killings, had ordered the two million people in the area to stay at home and shops to close in protest.

An aide to Maliki told Reuters he had “discussed” the lifting of the blockade with U.S. ambassador Zalmay Khalilzad and General George Casey, the U.S. military commander.

“The areas covered by the order are those places where there is terrible traffic because of the checkpoints,” he said.

Drivers have spent hours at a standstill in parts of the city as U.S. forces have hunted the missing military linguist, who was kidnapped, possibly by Shi’ite militiamen, while visiting Iraqi relatives in the eastern half of the capital.

“For days the people there have been suffering. It can’t go on,” the aide said. “Even if you have intelligence information, you can’t punish millions of people.”

Sadr, a firebrand young preacher, is a powerful figure within the Shi’ite bloc that dominates Iraq’s government. His Mehdi Army is a nationwide movement that controls police and much else in Sadr City and is blamed by the U.S. military and minority Sunni leaders for kidnappings and death squad killings.

An abortive U.S. raid against an alleged death squad leader in Sadr City that killed 10 people last week angered Maliki.

The military has not identified the missing soldier but Maliki told Reuters last week his name was Ahmed al-Taie and that he was snatched during a visit to relatives.

The New York Times on Monday quoted people who named Taie and said they were his relatives. They believed the kidnappers were from the Mehdi Army. They told the paper Taie had married a fellow Sunni Muslim this year and visited her frequently.