FALLUJAH, Iraq – The tactic in Fallujah is to advance, deliberately drawing fire from insurgents, so they can be pursued, encircled and subdued or killed. It’s dangerous work and the U.S. Marines step warily.

They squat, fire, dart a few feet and then squat and fire again. Squat, fire, squat and dart.

It makes for a lot of shooting. Mortars and rockets fly. Black smoke rises in the air.

And through the din, chants echo from the minarets of Fallujah telling the people to pray “that the fight will be over.” Calling upon Allah for help and reading from the Quran, the chanters urge residents to be patient. “Please let the fighting end soon,” they say.

On the whole, say the commanders of the 1st Battalion, 5th Marine Regiment, 1st Marine Expeditionary Force, the operation has gone well.

But sometimes the resistance stops them. That is what happened at two mosques here on Wednesday, officers say. Both mosques, they say, were being used as bunkers by the insurgents.

At the first mosque, said Maj. James Farnum, deputy commanding officer, “there were groups of maybe 20 to 30 people who engaged us” with small arms, rocket-propelled-grenades and machine guns.

“We flanked them,” he said. “We closed on them and we defeated them.”

The second mosque was tougher. Firing came from the mosque for several hours. Five Marines got hit, said division commander Maj. Gen. James Mattis.

Inside a Marine command post in a garage, the radio chatter between the troops near the mosque and the commanding officers grew intense.

“Enemy elements are dug in.”

“A company is under fire.”

“We have some bad folks dug in. They’re creating a problem. What should we do? We need backup.”

“No. We need regimental approval.”

“There are many, many mosques in Fallujah,” Lt. Col. Brennan Byrne, commanding officer of the battalion had said earlier. “Most of them are associated with hostile forces. But each will be treated as a unique case. We will not attack mosques willy nilly, but we will return fire.”

“If they run away we’ll go after them,” Mattis had said. “If they decide to fight from a mosque, we’ll take them out. We have to be precise. We don’t want to use any artillery barrages. We don’t want to fire into the next block.”

But, said Mattis, “if they profane the mosque by firing from it, the bottom line is if you shoot at us, we’re going to get tough with you.”

When approval came, a spokesman said the second mosque compound was hit from the air at least twice – once from a helicopter and once from a jet.

Until the past week, Fallujah was a no-go city for U.S. troops because it was considered so dangerous. Units of the 1st Marine Expeditionary Force then took up positions around the city but not in the middle of it. After the killing of four U.S. civilian contractors, the Marines advanced deep inside, meeting resistance all the way.

The Marines seem determined to track down those who killed the contractors here a week ago. They are distributing leaflets with photographs taken at the scene of that killing. “Wanted,” the leaflets say in Arabic. “If you have any information about who these individuals are, please call this number.”

But first comes the fighting.

“It’s just one fight after another,” said Lance Cpl. Ignacio Real. “If you kill somebody, you wait until the other guy comes out to drag him away and then you kill him too.”

“It’s real urban fighting,” said Percy Davila, 29, a medic. “It’s scary. You see RPGs (rocket-propelled-grenades) whizzing over your head and you have no idea where they’re coming from. If you cross the street, you put your head down and pray nothing will hit you.”

Davila was here before, during the invasion of Iraq a year ago. “Last time was much better,” he said. “Your job was to secure an objective, take it and wait for the next one. This time it’s 24/7.”

“This time it’s the little things that can kill you,” said Cpl. Richard Savick. “If you don’t pay attention, if you gaze off into space, if you take a turn too slowly, somebody can shoot you.”

“We make sure they display hostile intent” before firing on them, said Capt. James Edge. “We want to take the bad guys. We don’t want to make enemies. We do not want to kill women and children.”