Speaking on Monday, Colonel Mark Gurganus, the commanding officer of US marines in Falluja, vowed that fighters would not be allowed to regain control of their former stronghold.
"There is no doubt that the insurgency will rise in and around Falluja over the next few months as a lot of political developments take place," Gurganus said.
The Sunni Arab town, 50km (30 miles) west of Baghdad, was recaptured by US forces following a massive military incursion in November. Most of Falluja's 300,000 inhabitants fled at the time and about half have since returned.
With reconstruction of the city under way, more are now expected to return home. But the US military believes fighters are bound to come back with them.
"Now more and more people are returning to their homes and want to continue their livelihood which is what makes the city again sensitive to rebel attacks," Gurganus said.
Aljazeera.net spoke to a Falluja citizen who acknowledged efforts to bring Falluja residents back to the city. He complained that refugees are stuck in the middle between US forces and anti-US military fighters.
"People have been living in tents since more than a year. The US forces insist that no family returns to the city before it is 100% has no link to the fighters" Abd al-Qadir Zeidan told Aljazeera.net.
Residents undergo a security
check before being let home
"How long are they going to take until they are able to take all the city's inhabitants back?" he said. "Proving no link to fighters is something very tricky, because there are a lot of fighters who fight secretly without even their families knowing about them."
With a referendum on the constitution set for 15 October and general elections due by 15 December, opponent fighters are expected to renew their attacks in the city to disrupt the political process.
"With the referendum coming in the next two months and then the national elections, attacks will increase in Falluja even as we try to check each and every person entering the city," Gurganus said.
"I accept that the city is still dangerous... I still have to wear my helmet and body armour when I walk on the streets, but it is not what it was earlier"
Colonel Mark Gurganus,
US marines commander
"We have entry control points, but one can never guarantee that no bad guy can enter the city."
But he expressed confidence that fighters will be unable to carry out "spectacular" attacks on forces.
"There is no way they can try anything spectacular. There is no way they can take control of Falluja again," he said.
Accepting that the city remained dangerous, Gurganus said the combined security force of marines, Iraqi army and a newly established police force was ready to tackle any kind of fresh rebellion.
"I accept that the city is still dangerous... I still have to wear my helmet and body armour when I walk on the streets, but it is not what it was earlier," the marine officer said.
"Today we have three forces working together, though the Iraqi army and the police are still not completely professional as the cohesive unit of the marines."
Relatives grieve as the bodies
of the executed men are found
Gurganus said residents were also becoming pro-active and informing the security forces about rebel movements.
"A lot of information we get is coming from concerned citizens who offer tip-offs on possible IEDs (improvised explosive devices) or on unknown people entering the town and so on," the officer said.
Gurganus expressed confidence that strong voter participation in the coming polls will help break the armed opposition in this formerly defiant city of al-Anbar province.
"We have a city council now for Falluja, very soon we plan to have a proper judicial system and once the elections take place a lot will change and insurgents will not find shelter here," he added.
Dozens of Sunni tribal chiefs last week met senior US embassy and military officials, expressing willingness to take part in the constitutional referendum, though many spoke against federalist proposals in any draft charter.
Gurganus also felt that reconstruction of the war-damaged city will go a long way to instill a sense of security among residents.
"Proving no link to fighters is something very tricky, because there are a lot of fighters who fight secretly without even their families know about them"
Abd al-Qadir Zeidan,
"The rebuilding work is on, though not at a pace one would like it to be, but we are making progress each day, brick by brick and that will make people feel safe," he said.
US officials said more than $250 million has been spent to date on infrastructure projects in Falluja.
Of these funds, $125 million came from US coffers, while the rest came from the Iraqi government.
"I am optimistic that Falluja will be safe completely soon and we are not going out till that job is done," Gurganus added.
US and Iraqi forces are continuing to battle fighters, mainly Sunni Arabs, who are against the Shia and Kurdish-led government in Baghdad.
The bodies of 20 people, one of them beheaded, some of them shot and others with their hands bound behind their backs with plastic straps, were found dumped in southwest Baghdad, police sources said. Witnesses saw the bodies being taken to hospital.
A father cries over his son, one
of several men found executed
In Baghdad, an Interior Ministry official, Brigadier Salam Lutfi, was killed and two of his guards wounded when armed men opened fire on his car on a motorway in eastern Baghdad, a police source said.
Two bomb attacks on Sunday killed five US soldiers during patrols in Baghdad, a US military statement added.
One soldier was killed and two wounded when their patrol hit a landmine in al-Dura, south of Baghdad.
Four more soldiers were killed when their patrol struck a roadside bomb in southwest Baghdad.
In Kirkuk, one Iraqi soldier was killed and six injured when a roadside bomb struck near their patrol in Tuz Khurmatu, 60km south of Kirkuk, a police source said.
The US Defence Department has secret, detailed plans for sharp reductions in the number of soldiers on the ground in Iraq, Newsweek magazine reports in its upcoming issue.
Pentagon planners were targeting troop withdrawals to lower the US forces in Iraq from about 150,000 to 80,000 troops by the middle of 2006, according to two unnamed Pentagon officials cited by the magazine.
Further withdrawals would lower troop levels by the end of 2006 to the range of 40,000 to 60,000.