U.S. and Iraqi troops have stepped up air and ground assaults against suspected terrorist sites in the rebel bastion of Fallujah, west of Baghdad.

Residents report some of the most intense bombing so far, in a weeks-long campaign to rid the city of wanted terrorist Abu Musab al-Zarqawi and his loyalists.

Hospital officials say at least three people were killed in the overnight air strikes. Friday, ground troops took up positions inside the city.

Peace negotiations between the government and city leaders collapsed on Thursday. And Friday, local police say U.S. troops have detained the city's lead peace negotiator, Khaled al-Jumeili.

Meanwhile, in southern Baghdad, insurgents marked the first day of the Muslim holy month of Ramadan with a car bomb attack outside a police station. At least one person was killed.