"We have moved the battalion in to exploit the succes that we have had with the other battalion ... It brings a little more fire power," said US Captain Brad Gordon.

Gordon was referring to the arrival of the 1st Battalion of the 503rd Infantry Regiment, a unit under the 2nd Infantry Division.

Until now, the 2nd Battalion, 5th Marines, numbering close to 1,000, has cruised the streets and maintained eight combat outposts across the city. The army has patrolled the edge of eastern Ramadi and its northern suburbs.

The plan is "to continue ridding the city of its criminal elements. The whole point is to give the city back to the people of Ramadi," Gordon said, referring to the capital city of Iraq's turbulent western Al-Anbar province.

Major Mike Targos, the executive officer of the marine battalion, said "we are putting more forces inside the city proper. There is a repositioning of forces."

The influx of troops would allow army units to sweep villages south of Ramadi, which are thought to be providing haven to leaders of a bloody insurgency that has raged since last year's US-led invasion, said a military official.

Ramadi and Fallujah to the east appear to be on the brink of possible US-led offensives to wipe out the Sunni Muslim rebellion ahead of scheduled January national elections.

US army and marines have roped off Fallujah since mid-October and escalated air strikes there.