U.S. battles militants in Fallujah

FALLUJAH, Iraq -- Insurgents tried to break through the U.S. cordon surrounding Fallujah on Thursday as American forces launched an offensive against concentrations of militants in the south of the city. Some 600 insurgents, 18 U.S. troops and five Iraqi soldiers have been killed in the four-day assault, the U.S. military said.\nU.S. troops, meanwhile, went on the offensive Thursday in Mosul, Iraq's third largest city, after guerrilla attacks launched against police stations and bridges across the Tigris river in an apparent bid to relieve pressure on their trapped allies in Fallujah.\nA U.S. official acknowledged it might take "some time" to secure the city, 220 miles to the north.\nElsewhere, a series of attacks throughout central Iraq underscored the nation's perilous security. In Baghdad, a car bomb exploded Thursday moments after a U.S. patrol passed on Saadoun Street, killing 17 bystanders and wounding 30. There were no U.S. casualties.\nAnother car bomb exploded in Kirkuk as the governor's convoy was passing by, killing a bystander and wounding 14 people. Three Iraqis were killed in a shootout between U.S. troops and insurgents in Samarra. Two car bombs injured eight people in Hillah.\nAl-Jazeera television aired a videotape showing what the station said was an American contractor of Lebanese origin held hostage in Iraq. The balding, middle-aged man, who carried a U.S. passport and an identification card in the name of Dean Sadek, was shown sitting in front of a green wall. Al-Jazeera did not air any audio but quoted Sadek as saying all businesses should stop cooperating with U.S. authorities.\nThe four-day Fallujah offensive has wounded an additional 178 Americans along with 34 Iraqi soldiers, the military said.\nAs night fell, 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.\nAn 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.\nTwo 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.\n"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."\nMany, 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.\nCommanders said 1,200 to 3,000 fighters were believed in Fallujah before the offensive.\nMost 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.\nAmerican 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.\nOfficers said that suggested the insurgents were trying to break out of Fallujah rather than defend it.