The fighting here started as a series of well-coordinated Iraqi ambushes of routine Marine patrols. It turned into a day of nonstop, house to house, roof to roof fighting with Marines at times surrounded and holding on desperately.

It was a cacophony of fire for five or six hours, leaving the bodies of Iraqi attackers lying mangled in the dust, one with its head gone, but still clad in a vintage U.S.-made flak jacket.

Marines stepped warily around the Iraqi bodies, looking for their own comrades. American Cobra and Chinook helicopters thumped overhead, and Bradley Fighting Vehicles rumbled on the roads.

U.S. Marines with the 2nd Battalion 1st Marine Regiment take cover during a gunbattle with Iraqi insurgents on the outskirts of Fallujah, Iraq, Tuesday, April 6, 2004. Hundreds of U.S. Marines attacked several neighborhoods in the western Iraqi city of Fallujah in order to regain control of the city. (AP Photo/Murad Sezer)

At least 12 Marines were killed here, and 30 others injured. Ten of those killed were in Echo Company, which was the first unit attacked in Ramadi.

"They did a very heroic, very courageous job," the unit's commander, Capt. Kelly Royer, said.

The fierce daylong battle took place across this city of 350,00 people, 30 miles west of Fallujah, which is itself targeted and surrounded by coalition forces a week after four American civilian security guards there were killed, mutilated, burned and left hanging from a bridge.

The ambushes were launched in bright daylight by what appeared to be four well-armed and coordinated groups of attackers in units of 10 to 15.

Until yesterday, the recently arrived Marines in Ramadi said they had found two dozen makeshift bombs but encountered no open warfare, nothing like what erupted yesterday.

The patrolling Marines were slammed by M-16s, heavy machine guns, rocket-propelled grenades and mortars. The attackers appeared acquainted with the Marines' patterns of patrol.

Sunni insurgents guard the streets of Fallujah, Iraq, 65 kms west of Baghdad, Wednesday April 7, 2004. U.S. troops battled with insurgents in two central Iraqi towns Wednesday, with at least 60 Iraqis killed and more than 120 wounded in overnight fighting in Fallujah, hospital officials said. (AP Photo/Muhammed Muheisen)

The coalition forces responded with massive fire, armor and air support. Fighting raged around one street corner in particular and extended to other areas.

At one point, Marines fought house-to-house, some even leaping from one rooftop to the next as they chased and caught some of the insurgents.

As the fighting died off, at least four bodies were still lying in the dust while Americans went corpse-by-corpse looking first for their own.

Near the decimated shell of a U.S. humvee lay the body of one attacker clad in what Royer called an "old-style" surplus U.S. flak jacket.

An Iraqi man working for the Marines as a translator paced toward one of the bodies, kicked it, then turned away.

This Sunni-dominated city lies along the Euphrates River. As part of the larger battle against anti-coalition forces, the Marines have set up a base here they call Camp Hurricane.

By 2 o'clock this morning, the Marines of Echo Company, after a brief rest, were getting ready to set off again in search of the insurgents.

"We are going to find these thugs, these terrorists, and we are going to destroy them," said Royer.