The operation on Tuesday came as world powers and Middle Eastern states meeting in Egypt threw their weight behind the war-torn country's first free and multi-party elections in decades.

US marines and an Iraqi Swat (special weapons and tactics) team "swept through the south-central Iraqi town of Jabella, kicking off a fresh campaign in northern Babil province", the US military said in a statement. Jabella is 80km south of Baghdad.

The offensive involved more than 5000 Iraqi, US and British forces and follows the seizure of Falluja, the statement said.

"As the Iraqi people prepare to vote in nationwide elections in January, multinational forces are determined to capture or kill those who desire to destabilise the elections process," it said.

The joint operation resulted in the seizure of 32 suspected fighters, the military said, and US and Iraqi forces continued rounding up suspected fighters in house-to-house searches and vehicle checkpoints.