Nearly two dozen Americans have died in the fight to clear Fallujah of militants.
Lieutenant General Thomas Sattler, commanding general of the First Marine Expeditionary Force in Iraq, said the U.S. has "lost 22 coalition warriors who have made the ultimate sacrifice." he told reporters at a briefing that about 170 U.S. troops have been wounded. Five Iraqi soldiers have also been killed.
The announcement came as American forces went on the offensive against concentrations of militants in southern Fallujah who tried to break out of a security cordon. Guerrillas launched attacks in one of Iraq's major cities in what could be a bid to relieve pressure on their allies here.
Sattler also said 151 insurgents were being detained in Iraq and another 300 have surrendered at a mosque. The military estimates 600 insurgents have already been killed, about half the total of guerrillas thought to be in the city.
Sattler said U.S. and Iraqi forces now control about 80 percent of Fallujah. He said, however, that troops are searching "each and every house" for guerrillas, weapons and ammunition, "so there's much clearing to be done."
In other developments:
By Friday, Army and Marine units had pushed deeper into the southern reaches of Fallujah, backed by FA-18s and AC-130 gunships, as they sought to corner the insurgents.
With insurgent fire cover from nearby buildings, some three to four dozen militants tried to break out of the security cordon to the south and east of the city late Thursday but were pushed back by U.S. troops, the military said.
U.S. forces are also positioned to the west near key bridges, blocking rebels from crossing the Euphrates River with patrol boats.
In Mosul, Iraq's third-largest city, some 220 miles north of Baghdad, guerrillas assaulted nine police stations on Thursday, overwhelming battled U.S. and Iraqi troops around bridges across the Tigris River in the city. CBS News Reporter Charles D'Agata reports the government has ordered a full curfew in the city and closed off all roads leading in and out.
As night fell Thursday, U.S. Army soldiers and Marines attacked south of the main east-west highway that bisects Fallujah, a Sunni Muslim insurgent stronghold 40 miles west of Baghdad.
An Iraqi journalist in the city reported seeing burned U.S. vehicles and bodies in the street, with more buried under the wreckage. He said two men trying to move a corpse were shot down by a sniper.
Two of the three small clinics in the city have been bombed, and in one case, medical staff and patients were killed, he said. A U.S. tank was positioned beside the third clinic, and residents were afraid to go there, he said.
"People are afraid of even looking out the window because of snipers," he said, asking that he not be named for his own safety. "The Americans are shooting anything that moves."
Many, if not most, of Fallujah's 200,000 to 300,000 residents fled the city before the assault. It is impossible to determine how many civilians who were not actively fighting the Americans or assisting the insurgents may have been killed.
Commanders said they believe 1,200 to 3,000 fighters were in Fallujah before the offensive.
Most of the insurgents still fighting in Fallujah are believed to have fallen back to southern districts ahead of the advancing U.S. and Iraqi forces, although fierce clashes were reported in the west of the city around the public market.
American officers said the majority of the insurgent mortar and machine-gun fire Thursday was directed at U.S. military units forming a cordon around the city to prevent guerrillas from slipping away.
Officers said that suggested the insurgents were trying to break out of Fallujah rather than defend it.
At a U.S. camp outside Fallujah, Maj. Gen. Richard Natonski, commander of the 1st Marine Division, said the operation was running "ahead of schedule" but he would not predict how many days of fighting lay ahead.
"Today our forces are conducting deliberate clearing operations within the city, going house to house, building to building looking for arms caches," Natonski said. He said militants have been using mosques as military strong-points.
"In almost ever single mosque in Fallujah, we have found an arms cache," he said. "We have found IED-making (bomb-making) factories. We have found fortifications. We've been shot at by snipers from minarets."
The attacks in Mosul may have been intended to divert attention from Fallujah.
A U.S. military spokeswoman, Capt. Angela Bowman, said it could take "some time until we fully secure the city."
On Friday, armed militants attacked the main headquarters of a key Kurdish political party during an hour-long gunbattle that killed six rebels as Mosul's governor asked for security forces to stabilize the situation.