Time of U.S. Strike on Najaf Uncertain

The U.S. military and Iraqi security forces are preparing for a final attack on Muqtada al-Sadr's (search) Mahdi Army (search) militia in Najaf on the seventh day of fighting in that city, U.S. military officials said.

"Iraqi and U.S. forces are making final preparations as we get ready to finish this fight that the Muqtada militia started," said Col. Anthony M. Haslam, commanding officer of the 11th Marine Expeditionary Unit.

But the timing of the attack is unclear. Earlier Wednesday, it appeared a strike was imminent but a Marine officer said the U.S. assault had been postponed.

"Preparations to do the offensive are taking longer than initially anticipated," said U.S. Marine Maj. David Holahan. "It doesn't matter now, they know we're coming."

It was also unclear whether the assault would involve raiding Najaf's holiest site, the Imam Ali Shrine (search), which would infuriate Iraq's Shiite majority. The military said the insurgents are using the golden-domed shrine in Najaf's old city as a refuge and the governor has given U.S. forces permission to raid it.

Holohan, an executive officer of the 1st Battalion 4th Marines in Najaf, told FOX News that the American troops are taking their cue from the Iraqi forces, "who obviously know best what to do to defeat al-Sadr."

"We have enough firepower and training and equipment to deal with al-Sadr," Holohan continued. "There's really do doubt on our end ... as soon as we're given the signal to go" they'll strike.

Holohan said the people in Najaf have been supportive of the mission to root out the militia and actually have been "somewhat dismayed" that more hasn't been done sooner.

"The people in the town, they really want us to go forward," he said.

But Holohan clarified that it's al-Sadr's militia that's the target, not the cleric himself.

"We are going after the militia and the signal we're trying to give is, 'fight us and we'll destroy you,'" he said. "They're trained and they make us work a little harder to defeat them … it's not light and it's not easy but they're not capable of defeating us," he added.

The U.S. military has estimated that hundreds of insurgents have been killed in Najaf since fighting began last Thursday, but the militants dispute that. Five U.S. troops have been killed, along with about 20 Iraqi officers.

Al-Sadr loyalists launched mortar shells at U.S. forces moving into Najaf's vast cemetery — where 2 million people are buried — as American jets roared overhead. U.S. Marines and members of the Fifth Cavalry have been involved in intense firefights among the catacombs, tombstones and mausoleums sacred to Shia Islam.

The anti-American Shiite cleric al-Sadr has urged his followers to continue the battle even if he is killed. Al-Sadr himself is thought to be holed up in or near the Imam Ali Shrine. U.S. forces are wary of storming the building, however, for fear of upsetting the sensitivities of Iraq's Shiite population.

In other violence, a roadside bomb exploded in a market north of Baghdad on Wednesday, killing at least six Iraqis and wounding nine others, a hospital official said. The explosion shook the market in Khan Ban Sad, about six miles south of Baqouba, northeast of Baghdad.

"The place was crowded, but there were neither police or American patrols during the time of the explosion, and we are investigating this issue," said Baqouba police Col. Adnan Hussein.

Shiite Leader Killed

Also Wednesday, gunmen killed the head of a regional office of the Supreme Council of the Islamic Revolution in Iraq (search), the country's largest Shiite group.

Ali al-Khalisi, the head of SCIRI's Diyala province, was killed in Mahmoudiya, about 25 miles south of Baghdad, when gunmen drove up to his car and fired at him, said Haitham al-Husseini, a SCIRI spokesman.

And Iraqi police defused explosives found in a white gasoline tanker parked outside a hotel used mainly by foreigners in a busy shopping district in Baghdad.

The driver's cabinet was stacked with grenades and gasoline containers and rocket-propelled grenades, police and Interior Ministry officials said.

Meanwhile, the Iraqi government kicked a group headed by former Iraqi Governing Council member Ahmad Chalabi (search) out of its offices in downtown Baghdad. Staff at the Iraqi National Congress (search) were told to quit just days after their boss was accused of embezzlement and issued with an arrest warrant.

Chalabi denies the charges and his nephew Salem Chalabi (search) is also strongly refuting allegations that he was linked to a murder. Chalabi was on his way to Baghdad Wednesday to face the charges.

Violence in Najaf

On Wednesday, more militants entered a hotel scorched from fighting Tuesday to resume firing at troops. The U.S. military said the building was being used as a sniper's nest and a weapons storehouse and that about 20 people were killed inside.

"We keep pushing south and they just keep coming," said Capt. Patrick McFall, from the 1st Cavalry Division.

Ibrahim al-Jaafari, Iraq's new interim vice president, called on the U.S. troops to withdraw from Najaf.

"Only Iraqi forces should stay in Najaf, these forces should be responsible for security and should save Najaf from this phenomenon of killing," al-Jaafari told Arab TV network Al-Jazeera Wednesday.

Coalition forces said they were operating in the city at the request of the government.

Al-Sadr's fighters have been battling coalition forces for days in a number of Shiite strongholds in Baghdad and southern Iraq.

"I hope that you keep fighting even if you see me detained or martyred," al-Sadr said in a statement Wednesday. "I thank the dear fighters all over Iraq for what they have done to set back injustice."

To control movement in Najaf, Iraqi police and national guards blocked roads that connect the city's northern and southern parts Wednesday.

Shiite Communities in Distress

The fighting has plagued other Shiite communities across Iraq.

In Kut, 100 miles southeast of Baghdad, Iraqi police fought off attacks from the Mahdi Army at the town's central police station and other government offices.

"We gave orders to our forces to shoot anyone who gets near government buildings," said Mohammed Ridha, Kut's governor.

Violence persisted throughout the country's Shiite regions, with overnight clashes between insurgents and British forces in the southern city of Amarah killing 10 militants, according to hospital officials and witnesses. Another 50 Iraqis, including 20 militants, were injured, hospital officials said.

During the day Wednesday, British tanks were patrolling the major roads in Amarah, while Mahdi Army militants walked through the alleys, witnesses said.

Coalition forces also dropped leaflets from planes telling the people of Amarah that the fighting was only hurting the people of the city.

In the southern cities of Nasiriyah, Basra and Samawah, insurgents targeted coalition forces with mortars and rocket-propelled grenades, causing no injuries, Clooney said.

"The insurgents are using cover and buildings to (launch) indirect attacks rather than open conflict," he said.

Production resumed at Iraq's vast southern oil fields after authorities reached an accord with militant Shiites who had threatened to attack the country's vital export pipelines for crude, an Iraqi oil official told The Associated Press late Tuesday.

FOX News' John Cookson and The Associated Press contributed to this report.