Baghdad, Iraq ? Iraq’s prime minister has told Shiite militiamen to surrender their weapons or face an all-out assault, part of a commitment President Bush outlined on Wednesday to bring violence under control with a more aggressive Iraqi Army and 21,500 additional American troops.

Senior Iraqi officials said Wednesday that Prime Minister Nouri al-Maliki, under pressure from the U.S., has agreed to crack down on the fighters even though they are loyal to his most powerful political ally, the radical Shiite cleric Muqtada al-Sadr. Previously, al-Maliki had resisted the move.

Before Bush spoke, a senior Shiite legislator and close al-Maliki adviser said the prime minister had warned that no militias would be spared in the crackdown.

“The government has told the Sadrists: ‘If we want to build a state we have no other choice but to attack armed groups,”‘ said the legislator, who spoke on condition of anonymity because he was not authorized to speak for the prime minister.

Al-Maliki on Saturday announced that his government would implement a new security plan for Baghdad, which consists of neighborhood-by-neighborhood sweeps by Iraqi forces backed by U.S. troops.

In the past, the Iraqi government has tried to prevent American military operations against the Mahdi Army, while giving U.S. forces a free hand against Sunni militants. The Bush administration has pushed al-Maliki, who took office in May, to curb his militia allies or allow U.S. troops to do the job.

Although al-Maliki withdrew political protection from the Mahdi Army, there was no guarantee the Shiite fighters would be easily routed from the large and growing area of Baghdad under their control.

Iraqis inspect a destroyed house in which four members of a family died in the Sadr City area of Baghdad, Iraq. A police official and witnesses said the home was fired on by U.S. aircraft on Tuesday night. The U.S. military had no immediate comment. On Wednesday, Iraqi Prime Minister Nouri al-Maliki warned Shiite militants to disarm or face an all-out assault by U.S. forces.

The militia has more fighters, weapons and sophistication today than it did in 2004, when it battled U.S. forces to a standstill in two strongholds, the Shiite holy city of Najaf and Sadr City, Baghdad’s sprawling Shiite slum.

Sunni militants, meanwhile, have put up fierce resistance in the five days since al-Maliki announced his new security initiative for Baghdad.

Iraqi and U.S. troops have battled Sunni insurgents along Haifa Street in central Baghdad in two major battles.

Eighty suspected insurgents were killed in the fighting – 50 of them on Tuesday alone, in an assault backed by U.S. troops, fighter jets and attack helicopters.

In preparation for the new security plan, the Iraqi military will bring two brigades from northern Iraq, a region largely populated by Kurds, and one from the south.

Al-Maliki has not commented on the Bush administration’s plans to create a set of benchmarks to measure the Iraqi government’s progress on improving security.

Washington wants the prime minister to come up with a plan to equitably share the country’s oil wealth, ease restrictions on former Baath Party members and hold provincial elections – steps regarded as critically important to drawing Sunnis into the political process.