A top U.S. military commander in Iraq says insurgents in the city of Fallujah are moving "blindly" through the city without the ability to communicate or coordinate attacks.

Lieutenant-General John Sattler said today (Wednesday) that many insurgents fled ahead of the offensive, but the ones who have remained will be hunted down and killed.

American commanders in Iraq said earlier that U.S. and Iraqi troops control about 70 percent of the city, including key bridges and buildings.

Meanwhile, an Iraqi military spokesman says his troops have found houses in northern Fallujah used by kidnappers to keep and kill hostages.

And insurgents claimed to have kidnapped 20 Iraqi national guardsmen in Fallujah. In a video, the men were dressed in camouflage uniforms, but did not face the camera. The authenticity of the claim has not been verified.

As the battle to retake Fallujah rumbles on, insurgents in Iraq apparently have tried to open other fronts to distract U.S. and Iraqi troops, launching attacks in several cities that have killed at least 28 people.

In Baghdad, police say at least seven people have been killed in an explosion near a police checkpoint. The prime minister (Iyad Allawi) has also extended the closure of the capital's airport for another 24 hours because of the escalating violence.

To the north, in Baiji, at least nine people were killed and 24 wounded in fierce fighting. A curfew has been imposed on the town.

And in Mosul, the governor's office has also imposed a curfew after five people were killed in several clashes.

Elsewhere, the U.S. military says an American soldier was killed and another wounded in a roadside blast in Balad, north of Baghdad. And farther north (near Tuz), roadside bombs killed six Iraqi soldiers.