U.S Marines backed by warplanes and helicopter gunships battled insurgents in Fallujah (search) on Wednesday, killing 20, as a day-old attempt to bring peace to the besieged city faltered.
Marine commanders said guerrillas were not abiding by a call to turn in heavy weapons that is central to an agreement on scaling back the confrontation. A number of weapons were turned in Wednesday, but 95 percent were already unusable, commanders said on condition of anonymity.
Explosions were heard coming from the scene of the fighting, and Cobra helicopter gunships (search) were blasting from the air. Tanks moved into the Julan neighborhood from which Marines said insurgents their positions.
Marine Lt. Col. Brennan Byrne said high-level commanders viewed the battle as a "major breach" of the agreement. "The implication of that I don't know yet," he said.
In response to what the Marines called a disappointing disarmament showing, the Marines halted a key commitment on their side in the deal -- the return of Fallujah residents to the city. The Marine commanders would not say how many weapons had been turned in.
About 10 families made it back into the city in the morning before Marines announced to some 600 Iraqis waiting at the checkpoint that no more would be allowed to enter. The crowds massed behind concertina wire, with women and crying children pressing forward, demanding to be let in. Nearby trucks were stacked high with families belongings and other goods.
Some 70,000 people -- more than a third of Fallujah's population of 200,000 -- fled the city during the fighting since April 5, flooding Baghdad (search) and nearby areas.
Wednesday's battle began with an ambush by 13 insurgents on Marines, who called in Cobra gunships that killed 10 of the attackers, Byrne said. Nearly three dozen insurgents then joined the fight with Marines in a running battle that lasted four hours. It ended when warplanes dropped two 500-pound bombs. Ten more insurgents were killed, Byrne said.
U.S. officials have said the deal's success hinges on whether the Fallujah negotiators -- a group of local civic leaders -- can convince the guerrillas to comply with the call to hand over their arsenals. The military has warned it may resume its assault on the city if the agreement falls through.
Implementation of the deal reached by U.S. officials and Fallujah civic representatives began with a spirit of optimism on Tuesday.
Several hundred Iraqi police and security forces moved back into the city, and a curfew was pushed back by two hours to 9 p.m. Announcements aired in the city detailed how residents should turn in to police and city officials any heavy weapons such as rocket-propelled grenades, machine guns, rockets and bomb-making material.
By noon Wednesday, Byrne said no weapons had been turned in.
"These may be early indications that the insurgents may not be living up to the requirements of the agreement," he said.
Later, commanders said some weapons had been surrendered, but almost all were useless.
Insurgents opened fire with small arms overnight and fired a rocket-propelled grenade at the Liaison Office where Iraqi security forces are suppposed to hand over to the U.S. military any weapons they collect.
During the day, some 300 members of the police and security forces who had left the city were lined up to "re-enlist," said Capt. Steve Coast -- meaning they would receive new documents certifying they are members of the force.
Fallujah's mayor was also working from the site. Several hundred other security forces moved into the city Tuesday.
U.S. commanders have warned that they could launch an all-out attack on the city if the agreement -- announced Monday after negotiations between U.S. officials and Fallujah civil leaders -- falls through.
So far, the U.S. response has been the halt to the return of families who fled Fallujah during the fighting -- a top concern of the Fallujans. A day earlier, U.S. officials allowed 50 families back into the city as provided for under the deal.
From the start, the fragile agreement had depended on how much the city's guerrillas complied with a call by city officials for them to turn in heavy weapons.