The US military says an estimated 600 what it terms insurgents have been killed since the start of the battle of Fallujah on Monday.
But officials cautioned that the death toll was only a rough estimate, and would change as bodies delivered to hospitals and morgues began to be tallied.
The toll takes into account fighters killed in ground fighting, as well as by hundreds of air and artillery strikes that have collapsed buildings and pounded insurgent positions.
Eighteen US troops have been killed and another 69 wounded in this week's offensive to take control of the rebel-held Iraqi city Falluja, a senior US Marine Corps commander said.
Five Iraqi troops fighting alongside the Americans also have been killed in the ground assault on the city, while 34 Iraqi security forces have been wounded in action, Maj. Gen. Richard Natonski, commander of the 1st Marine Division, told a briefing in Falluja monitored at the Pentagon.
America's top general hailed the Fallujah offensive as being "very, very successful," despite suspicions that many rebels had simply fled before it began.
"Hundreds and hundreds of insurgents" have been either killed or captured, Air Force General Richard Myers, Chairman of the Joint Chiefs of Staff, said today
"We hope that in the next few days we'll be able to return Fallujah to the citizens there without the intimidation that the insurgents brought," he said
The US military
has admitted that
two US attack helicopters were shot down in separate incidents near Fallujah today.
One of the choppers was hit nine miles northwest of Fallujah; the other was hit a mile southeast of the city.
The pilots were not injured, and other helicopters rescued them from the area, the military said.
US forces attacked southern Fallujah with airstrikes and artillery in preparation for a ground assault on fighters trapped in this part of the former militant stronghold.
In the past 24 hours of fighting, three US troops have been killed, while another 17 were wounded in Fallujah, the US military said.
US troops were reportedly advancing through the city from the northern end, pushing militants slowly into the southern half of Fallujah. With US units positioned to the south and east, and the Euphrates River on the west, fighters are being squeezed into a corner, the military said.
An Iraqi commander has reported the discovery of "hostage slaughterhouses" in which foreign captives had been killed.
Anti-US fighters have sought to open a second front elsewhere in Iraq, mounting attacks outside Fallujah and kidnapping three relatives of Prime Minister Ayad Allawi. Militants also claimed to have abducted 20 Iraqi National Guard troops in Fallujah.
The latest kidnappings were part of a surge of attacks outside the city
- an attempt by militants to divert US-Iraqi forces.
Fallujah, 40 miles west of Baghdad, is the centerpiece of the Sunni Muslim insurgency that has stymied US efforts to secure Iraq and prepare for national elections that are scheduled for January.
Both Super Cobra helicopters were hit with rocket-propelled grenades and small arms fire and were forced to land, the military said.