FALLOUJA, Iraq — Nine months after U.S. and Iraqi troops killed an estimated 1,000 insurgents here in a battle that also cost more than 70 American lives, intelligence suggests that rebels are trying to filter back into the former capital of Iraq's guerrilla movement.
American commanders in Baghdad and Fallouja say they control the city so completely that the guerrillas cannot regain a foothold. But they acknowledge that Fallouja remains a powerful icon to an insurgency that is keen to stop Sunni Muslim Arabs in western Al Anbar province from participating in an October referendum on Iraq's proposed constitution.
"In their minds, I think it's got significance because a lot of insurgents were killed there," Army Lt. Gen. John R. Vines, the commander of coalition forces in Iraq, said in Baghdad.
"This was a resounding defeat for them," added Brig. Gen. Peter Vangjel, who oversees analysis of operations, "and they want it back."
The prospect of insurgents infiltrating the city presents a daunting problem for military officials. For the embryonic Iraqi government as well as the U.S.-led coalition, commanders say, what happens in Fallouja will symbolize the success or failure of the war.
If insurgents succeed in returning, it would amount to rolling back the coalition's largest military victory since the fall of Baghdad in April 2003.
The Marines' allowing former Fallouja residents to return has added to the concern. So far, 140,000 of the city's 250,000 residents have come back to a landscape littered with rubble, its skyline broken by tilting minarets.
As the Marines continue to relax restrictions on the city's entry points, intelligence leads suggest that insurgents who have already entered Fallouja and others who may soon return have continued to plan attacks on Americans.
Fallouja Mayor Dari Ersan reflected that concern as he prepared to leave the barricaded fortress that serves as City Hall after a recent meeting.
As a Marine officer explained the procedure for arming the city's new squadron of personal security guards, Ersan cut him off.
He was worried about getting home that night.
"Just give me a pistol," he said. "I'm talking about my own security."
Marine Maj. Gen. Stephen T. Johnson, commander of coalition forces in western Iraq, said it was not surprising that insurgents would want to return to Fallouja. As he spoke, eight U.S. artillery blasts, apparent retaliation for a guerrilla mortar or rocket strike, rattled the windows behind him. Johnson didn't flinch.
"Every time a bomb goes off in Fallouja, people say, 'Here they come. Here it comes again.' We expect that there will be insurgent activity in town. And if he tries, we will continue to defeat him as we have in the past," he said.
So far, there is little evidence in the street of the insurgents' return. U.S. troops who took the city center door by door late last year now roll through in the beds of open-backed Humvees. One group stopped to walk the streets as a Western reporter talked to Iraqis, a liberty unavailable in other major cities in Iraq's perilous Sunni Triangle.
When an 11-year-old boy brandished a realistic toy gun, a potentially fatal move, the Marines offered him a deal: his "gun" for a handful of bubble gum.
"Good trade," the boy said in Arabic.
"Yeah, good trade," a Marine agreed. "Your life for gum."
Still, beneath the seeming placidity lies a hostile city, said Staff Sgt. Ryan Powell, a Marine reservist who in his civilian life is an LAPD officer who patrols one of Los Angeles' most volatile neighborhoods.
"It's a lot like South-Central," Powell said with a shrug. "Nobody wants to talk to you. They say, 'If I talk to you, I'll be a target.' But in L.A., you don't have to worry about someone driving a car and turning into you at the last minute to blow you up."
Residents here have never been very interested in talking to strangers. During Saddam Hussein's reign, "for 35 years the way they survived was by not seeing things," a U.S. officer said.
The current insurgency has deep roots here, and before the U.S. push to drive them out, "they were everywhere, like rats," fruit vendor Fareed Hamad Khalaf said as his melons baked in a 120-degree swelter. "Some are killers. Some are like me, wearing civilian clothes. We don't know who they are. Some of them will sneak back into the city. Some already have."
Marine Sgt. Kent Padmore vividly recalled the July day when a suicide bomber wheeled his car into Padmore's convoy, exploding it into a truck carrying Marines back to their base. In the blast and the shootout that followed, five Marines -- three of them women -- and one sailor were killed.
Padmore, now recovered from burns he suffered in the attack, rushed to the overturned truck in front of him to find the gunner cut in half and a female Marine crushed beneath the vehicle.
Some Marines were tired that night, he recalled. Now, he added in the accent of his native Trinidad, they hardly blink.
"Their tiredness goes away," he said. "Everyone is alert."