Thousands of U.S. and Iraqi troops have pressed on with their assault against insurgents in Fallujah, as rebels struck back elsewhere in the country with car bombs and other attacks.

A top U.S. general (Richard Myers) said today (Thursday) that hundreds of insurgents have been killed or captured since the operation was launched Monday night. The U.S. military confirmed that 18 American service members and five Iraqi troops also have been killed.

Meanwhile, a powerful car bomb exploded near a police patrol in a busy commercial district of Baghdad, killing at least 17 people and wounding many others.

To the north, in Mosul, fierce clashes erupted and the provincial governor called in U.S. air and ground support against the rebels.

Violence was also reported in Kirkuk, Hillah, Ramadi and Samarra.