Those tensions erupted publicly last week, to be followed by shows of reconciliation.

On Wednesday, Mr. Maliki challenged an American assertion that the two governments had agreed on a timetable for stabilizing Iraq. On Thursday and Friday, he issued angry comments pointedly voicing his independence from the Americans, including an account circulated by his aide of an acrimonious meeting with Mr. Khalilzad, during which Mr. Maliki was said to have told the ambassador that he was “a friend of the United States, but not America’s man in Iraq.” On Saturday, the White House convened a videoconference at which Mr. Maliki publicly praised President Bush.

Image The 172nd Stryker Brigade took down a checkpoint in the Karada neighborhood of Baghdad yesterday in response to the prime ministers orders. Credit... Karim Kadim/Associated Press

The abrupt declaration by Mr. Maliki on Tuesday followed a visit to Baghdad on Monday by President Bush’s national security adviser, Stephen J. Hadley, who was here to discuss how to reverse the country’s slide toward all-out civil war.

Violence continued to torment the country on Tuesday, including the mass kidnapping of at least 50 civilians by gunmen on a road north of Baghdad, and the announcement that 2 more American troops had been killed, raising the toll of American deaths this month to at least 103.

Mr. Maliki had been under pressure from his Shiite backers to push the Americans to lift an eight-day-old cordon around Sadr City, where American authorities believe the kidnapped American soldier is being held.

The soldier was abducted in the central Baghdad neighborhood of Karada on Oct. 23 after leaving the fortified Green Zone without authorization. Three people were detained early Tuesday in the latest raid in Sadr City as part of the manhunt, the American military said. Although the military has not released the name of the soldier, members of an Iraqi family who said they were the missing soldier’s in-laws identified him as Ahmed Qusai al-Taei, 41.

Moktada al-Sadr, the powerful Shiite cleric who counts Sadr City as his greatest bastion of support and who wields considerable influence in Mr. Maliki’s ruling Shiite coalition, called for a general strike in the neighborhood on Tuesday to protest the cordon. In its search for the soldier, the American military has singled out the Mahdi Army militia, which has grown increasingly fractured but still answers in part to Mr. Sadr.

Joint American-Iraqi roadblocks and checkpoints at the entrances to the neighborhood, and others erected in Karada, have caused major traffic jams, impeded commerce, turned short commutes into ordeals lasting hours and provoked the ire of Iraqis. On Monday, Mr. Sadr, who led two uprisings against American troops in 2004, threatened unspecified action if the American “siege” continued.