US forces have launched new air strikes and artillery attacks against rebels in the south of the Iraqi city of Falluja, as fighting raged across other cities.
US soldiers say house searches have yielded many weapons caches
War planes attacked an underground bunker and steel-reinforced tunnels, a US military statement said.
With the assault in its second week, US commanders say they occupy Falluja, but are expecting more stiff resistance.
In these last hours and days of the attack, the fighting is more frantic, says the BBC's Paul Wood in Falluja.
In other developments:
- US warplanes drop bombs on insurgents in Baquba, west of Baghdad
- At least six Iraqi troops are killed in the city of Mosul as two police stations are stormed, witnesses say
Militants release two female relatives of Iraq's interim Prime Minister, Iyad Allawi, kidnapped last Tuesday with his elderly male cousin, Ghazi. There is no word on him
- A US soldier is charged with "premeditated murder and conspiracy to commit premeditated murder" against an Iraqi.
Rebels' last stand?
US troops, backed by Iraqi soldiers have pushed the insurgents to the southern edge of Falluja, beyond which the desert and more US troops await them, says our correspondent, who is with the US marines.
Maj Gen Richard Natonski says there are a few determined fighters left.
"I think what you're seeing now are some of the hardliners. They seem to be better equipped than some of the earlier ones... we've seen flak jackets on some of them and I think they're probably willing to lay down their lives in the fight. But we're more determined and we're gonna wipe them out."
Many houses in the south of the city have been found full of weapons.
It seems the insurgents believe this was the direction from which the initial assault would come, our correspondent says.
Bodies left lying
Outside the US base in central Falluja, bodies lie in the streets, being gnawed at by dogs and cats.
This will pose a serious public health risk for any refugees who might eventually want to return, says our correspondent.
The marines are taking occasional sniper fire and cannot recover the bodies or even the weapons on them.
The US military says it has killed about 1,200 militants. Thirty-eight US soldiers have been killed and 275 wounded so far. Six Iraqi government troops have also died.
There are no figures on civilian deaths. US military officers say they believe civilian casualties are small because so many people fled the city before the assault began.
An Iraqi government delegation is due to go to the marines' headquarters to help assess the condition of civilians.
The Iraqi Red Crescent - one of the few aid agencies operating in Iraq - says it is still negotiating with the Americans after being denied access to the city.
It said there was a desperate need for food, clean water and medical supplies, as hundreds of civilians were still hiding in their houses, without drinking water and running low on food.
The Americans have said they can take care of Falluja's humanitarian needs themselves.
Military civil affairs teams are poised to begin giving out millions of dollars in compensation.
But one US officer said it could take a month to restore water supplies properly in the city.
The US-led assault on Falluja is aimed at stabilising the country before planned elections in January.