Myers, the chairman of the US Joint Chiefs of Staff, arrived from Kuwait Tuesday at a military base near Baghdad's airport with comedian Robin Williams, American football Hall of Fame inductee John Elway and US model Leeann Tweeden.

His visit Tuesday comes as US and Iraqi forces struggle to bring order to the country ahead of national elections scheduled for January 30, with the US death toll also mounting almost daily.

Myers acknowledged that a spike in violence was likely ahead of the polls but that the elections needed to go ahead as planned.

"We said all along that violence will increase as we move towards the elections... They (insurgents) will stop at nothing to try to keep Iraq from becoming a free country.

But delaying the elections would "give leverage to the insurgents," he said.

Myers said US troops levels would reach 150,000 through the election period and that any decrease would depend on security following the polls.

At least eight Iraqis have been killed in two suicide car bomb attacks in as many days near an entrance to Baghdad's fortified Green Zone, which houses the interim Iraqi government and foreign embassies.

Eleven US troops have also been killed in fighting since Saturday, mostly in Iraq's restive western province of Al-Anbar, where the former rebel stronghold of Fallujah is located.

Myers told reporters "there was still work to be done, still pockets of people that have to be dealt with" in Fallujah, but that small numbers of residents should be able to return to the city "in the next few days".

Myers was last in Baghdad November 15 during the US-led military's massive assault on Fallujah and also visited Iraq in April and May of this year.

The Sunni Muslim city was the scene of heavy fighting over the weekend, an AFP correspondent embedded with the marines there said, forcing the military to call in air strikes on rebels positions.

Most of Fallujah's 250,000 residents fled the city before the November 8 assault to wrest the city away from insurgents who the military says were using it as a base from which to wage a campaign of terror across Iraq.

Myers said Fallujah had yielded "a lot of good intelligence" and that the insurgency would not again be able to find as good a base to operate from.

When asked about reports of hundreds of rebel fighters returning to the city, he said there was information that a few insurgents would try to filter back into Fallujah with returning refugees, "but they will be dealt with by Iraqi security forces and US forces".

As Myers spoke, several thousand US troops watched a concert given by Williams and lined up for autographs from Elway and Tweeden.