On a recent afternoon, two Iraqi National Guardsmen at a checkpoint at the government center watched as a group of marines walked up. "Here come the sons of dogs," one guardsman said to an Iraqi reporter.

Next door, in police headquarters, Iraqi officers tossed around conspiracy theories.

"The Americans gave us nothing more than AK-47's so they could stay in Iraq for a long time," Lt. Abdul-Latif Salim said. "The resistance has the right to fight the occupation. It's an obligation for every Muslim. The Allawi government has no power."

Insurgents have tried discrediting the marines and the local government through widespread propaganda. Clerics regularly preach against the occupation, while guerrillas post the names of Iraqi security officers outside mosques. A marine showed a flier seized from a mosque that depicted a woman in a black robe being raped by men in sunglasses, presumably Americans.

In late September, insurgents began blowing up whole buildings downtown, videotaping the demolitions and giving the tapes to Arab television networks to attribute blame to American airstrikes, Marine officers said. The explosions have destroyed an agricultural center, a veterans' building and the Red Crescent headquarters. Their wrecked facades still scar the city.

As in other parts of Iraq, guerrillas are killing locals working with Americans. An interpreter at a base called Combat Outpost, east of downtown, was found beheaded recently. Insurgents even killed the man who cleaned the portable toilets at the base.

Sergeant Keefer said the marines tried calling a list of 100 potential local contractors when they first arrived. Many of the phone numbers had been disconnected, and people who did answer said the contractors had left town. Reconstruction "is pretty much at a standstill right now," said Capt. Sean Kuehl, an intelligence officer. "An insurgency cannot be defeated solely by an occupying power. We need the support of the local population."