Blue-shirted Iraqi policemen crept through an alley early Tuesday, training gun barrels on empty doorways and rooftops as part of U.S. Marine-led preparations for joint patrols in Fallujah (search) this week.

The joint patrols beginning Thursday are a crucial part of the negotiations to save a fragile truce and avoid an all-out Marine offensive against insurgents. Fighting in the city west of Baghdad (search) has killed hundreds of Iraqis and at least eight Marines since April 5.

Fighting erupted again Tuesday for a second straight night with a U.S. AC-130 gunship hammering targets in the city. Gunfire and explosions reverberated for nearly two hours, and an eerie orange glow shone over the area while showers of sparks descended like fireworks. Whether the U.S. assault would change plans for the joint patrols wasn't immediately known.

On Thursday, the Iraqi policemen planned to push past the front lines and one U.S. officer said they would likely come under fire. An Iraqi officer brushed off the warning, saying his concerns are restoring order and denying U.S. forces any excuse to stay.

Training began Monday in the city's labyrinthine industrial sector, a cluttered zone of auto garages and factories on Fallujah's southern edge that is under heavy guard by U.S. forces.

Marine trainers are rapidly running through the basics of weapons handling, marksmanship, firing positions and hand signals to help the Iraqis communicate with the Marines.

There won't be any drills with live ammunition, partly because the area remains tense. Marines holed up in vacant factories in the zone occasionally come under attack by snipers.

Iraqi security men in Fallujah said they're worried they'll be branded collaborators for working with the Marines.

But Iraqi 1st Lt. Adel Hamid shrugged off those concerns.

"First comes the security of the country," Hamid said. "I don't want to leave any excuse for U.S. forces to stay in Fallujah."

Several U.S. officers said they were worried that the patrols might become targets for gunmen and that the Iraqi security forces might not fight well.

On Tuesday, Iraqi police in crisp blue shirts and members of the U.S.-trained Iraqi Civil Defense Corps (search) moved around grain silos and empty warehouses, crouching in combat firing positions. They spun around, training unloaded AK-47 assault rifles on blackened doorways, windows and rooftops.

Marines occasionally sought to correct the way the Iraqis held their weapons. "Keep your eyes open," said one of the Iraqi translators, wearing desert camouflage fatigues and tennis shoes.

After the men moved through an alley, their boots and sandals crunching broken glass underfoot, a Marine told them to be sure to space themselves farther apart. If someone had lobbed a grenade, he explained, they all might have been killed.

"You could tell it was the first time some of them handled a weapon," said Marine Master Sgt. Roland Salinas. Among the top concerns of the Marines is to avoid friendly fire, he said.

Sgt. Cameron Lefler told the group of 30 Iraqis that he saw improvement, but urged them to stay focused.

The patrols will avoid the city's northern Jolan district, a poor neighborhood that is a stronghold of the insurgents. Insurgents in Jolan attacked Marines with gunfire and rocket-propelled grenades on Monday, setting off intense battles that killed one Marine and eight Iraqis.

On Tuesday night fires were visible in Jolan, and mosque loudspeakers elsewhere in the city called for firefighters.