In one of those probes, American military prosecutors were expected to charge seven Marines and a Navy corpsman in the death of an Iraqi civilian, a lawyer who represents two of the Americans said late on Thursday.

Marine officials "told us charges would come Friday, but then let us know they probably will not release them until Monday," said attorney David Brahms, who declined to identify his clients.

The eight men are being held in the brig at Camp Pendleton in the April 26 killing of a Hamandiya man and a subsequent attempt to make the dead Iraqi appear to be an insurgent by placing an AK-47 rifle near his body.

Asked if the United States would hand over the Haditha files, Khalilzad said the matter had not yet been discussed. But he said a meeting about Haditha would be held later on Friday with the top U.S. commander in Iraq, General George Casey.

Maliki has moved quickly to assert his authority since taking office.

He declared a one-month state of emergency and launched an "iron fist" security crackdown on Thursday in the southern city of Basra against gangs and feuding Shi'ite factions threatening oil exports.

During his visit to the Baghdad power plant on Friday, Maliki suggested he was prepared to launch a major offensive against al Qaeda militants and insurgents in the western city of Ramadi if necessary.

"We are trying to reach reconciliation with the people of Ramadi. Force will only be used as a last resort, but if all other measures fail we will use force," he said.

Aside from security, most Iraqis are concerned with poor basic services such as electricity, which they enjoy for only a few hours a day.

Maliki, surrounded by a small army of western and Iraqi security guards, sought to reassure Iraqis that a strategy has been developed to improve power supplies.

But the manager of the Baghdad South Power Plant, Abdel Karim Lafta, complained that his employees badly need training and workers said they feared for their lives when they left the plant because it was built by the United States.

"Every time we walk home after work I wonder if I will be killed by terrorists or a roadside bomb," said Nabil Fatih.

Earlier, two bombs ripped through one of Baghdad's oldest and most popular street markets in quick succession, killing at least four people and wounding 50, police sources said.

Reuters television footage showed bloodstained debris from market stalls in the center of the capital, where Baghdadis buy and sell birds and other live animals.