FALLUJAH, December 1, 2004 (AFP) - Iraqi rebels are creeping back into areas cleared by US marines in Fallujah, where the military continues daily to secure homes and try to seize weapons caches before they can be used to again attack US and Iraqi troops, marines say.

"The last few days we found 20, 25 guys in houses that were already cleared," said one marine.

Patrols from the 1st Battalion, 3rd Marines were searching blocks in north Fallujah Tuesday, combing through abandoned homes which repeatedly yielded weapons they say have been stashed by insurgents who continue to put up sometimes stiff resistance.

A massive US and Iraqi assault launched November 8 to wrestle the Sunni-Muslim enclave away from rebels has broken the back of Iraq's insurgency, according to top US military officials.

Fallujah has largely been quiet for days, with marines encountering only pockets of resistance -- small groups of rebels either caught hiding out in buildings or hitting patrols in hit-and-run ambushes.

But marines Tuesday were taking no chances as they blasted homes with heavy machine-gun fire and grenades before climbing from roof to roof and storming the empty buildings, according to an AFP correspondent embedded with the unit.

Several weapons, including assault rifles and anti-armor rounds, were found in bedrooms and kitchens littered with clothes and broken crockery, the correspondent said.

On Monday, similar patrols turned up a much larger cache of some 70 assault rifles and 22 RPG (rocket-propelled grenade) launchers, as well as hundreds of rounds of ammunition, bullet-proof vests with "police" written across them and computer equipment, said Captain Tom Tennant.

He said suspected rebels have been caught turning up at food distribution centers, and several attacks have occurred in areas of the city that have been described by some military officials as Fallujah's Green Zone.

"We cleared an area up here," he said, pointing to a corner of a map of his unit's sector, "and then saw some guys running around in there."

Drawing his finger down a few blocks, he said: "They ran down here and engaged some of our guys in a firefight."

Marines at 1-3 Charlie Company's small toe-hold in the city, an abandoned school surrounded by sprawling homes in the largely affluent neighborhood, say they have been frustrated by rebels who appear beaten one day, only to turn up again another.

But they also say with increasingly fewer marines -- several units have already left the city following the November attack -- there is virtually no way to keep rebels from taking up refuge in cleared buildings.

"If you want to keep this place secured, you need a whole lot of bodies," said one marine corporal.