IMPEACH BUSH

BAGHDAD - American convoys under the protection of Blackwater USA resumed on Friday, four days after the U.S. Embassy suspended all land travel by its diplomats and other civilian officials in response to the alleged killing of civilians by the security firm.

A top aide to Prime Minister Nouri al-Maliki had earlier conceded it may prove difficult for the Iraqi government to follow through on threats to expel Blackwater and other Western security contractors.

The aide, who spoke on condition of anonymity because the investigation into Sunday's incident was ongoing, said a way out of the Blackwater crisis could be the payment of compensation to victims' families and an agreement from all sides on a new set of ground rules for their operations in Iraq.

U.S. Embassy spokeswoman Mirembe Nantongo said the decision to resume land travel outside the heavily fortified Green Zone was made after consultations with the Iraqi governments. She said the convoys will be limited to essential missions.

Nantongo declined to comment on an Interior Ministry report that officials said concluded that Blackwater guards opened fire from four positions on a square in western Baghdad after a vehicle near their convoy failed to stop in the incident on Sunday.

"We're waiting for the results of the investigation, which we are conducting as quickly as we can," she said.

The U.S. ban announced Tuesday had confined most American officials to the Green Zone, a 3 1/2-square-mile area in the center of the city that houses the American Embassy and thousands of U.S. soldiers and contractors.

The decision kept them from visiting U.S.-funded construction sites or Iraqi officials elsewhere in the country except by helicopter — an indication of how dependent the State Department is on Blackwater protection.

Blackwater has said its employees acted "lawfully and appropriately" in response to an armed attack against a U.S. State Department convoy. Several Iraqi witnesses and officials claim the security guards were the first to open fire.

U.S. and Iraqi officials have formed a joint committee to probe the widely differing versions of Sunday's deadly shooting allegedly involving Blackwater security guards.

Interior Ministry spokesman Maj. Gen. Abdul-Karim Khalaf said a report found that the security guards opened fire first on Iraqis who were driving in their cars.

The report, Khalaf said, recommended annulling a legal provision that gives immunity to foreign security companies operating in Iraq. It also recommended Blackwater pay compensations to the victims' families and that all foreign security companies be replaced by Iraqi security companies.

According to Khalaf, a car bomb detonated around noon Sunday near al-Rahman mosque in Mansour, a mile north of Nisoor Square. "Minutes later, two mortar rounds landed nearby Nisoor Square and they (Blackwater) thought that they were under attack," Khalaf said.

"They started shooting randomly from four positions in the square, killing 11 civilians and injuring 12 others. The first one who was killed was a driver who failed to stop and then his wife," Khalaf said.

A U.S. official in Washington who is familiar with information collected by investigators said the accounts given by witnesses are widely different but most agree that Blackwater guards fired on a car that was acting suspiciously. The car then burst into flames and exploded, the official said, citing Iraqi witness accounts.

Americans who were at the scene maintain they were taking fire before the car approached and fired back. Some insist the car exploded without being hit, the official said, declining to be identified before the investigation is final.

President Bush has said he expects to discuss the shooting with al-Maliki during a meeting in New York next week on the sidelines of the U.N. General Assembly session.

"Folks like Blackwater who provide security for the State Department are under rules of engagement," Bush said. "They have certain rules. And this commission will determine whether their violated those rules."

Associated Press writers Qassim Abdul-Zahra and Sinan Salaheddin contributed to this report.