The northern Iraqi city of Mosul has seen dozens of attacks on U.S. troops in recent weeks, sparking fear that anti-coalition violence has spread northward from Saddam Hussein supporters' strongholds in the so-called Sunni Triangle, north and west of Baghdad. It is late Sunday night and the soldiers at the command post of the Third Battalion, 327 Infantry in northern Mosul receive an unusual guest.

A local Iraqi taxi driver has driven over to the base with a carload of large mortar rounds. He tells the soldiers that he had just foiled an attempt by terrorists to kill American soldiers.

The driver, Ibrahim Khalil Ismail, says two men carrying large bags and handguns tried to steal his car on a crowded street earlier in the evening. When the engine of his car would not start, Mr. Ismail said the men became nervous and abandoned the car, leaving the bags of mortars inside the vehicle.

Mr. Ismail said the would-be carjackers put a gun to his head and told him to get out of the car. He says the men told him that they were planning to use the car and the mortars rounds to blow up U.S. troops in Mosul.

The description of the men's plans did not surprise the soldiers in this city, the third largest in Iraq. Since the start of the Islamic holy month of Ramadan on November 1, there have been numerous daily attacks against U.S. troops here, including roadside bombings and deadly assaults on military convoys and patrols with rocket-propelled grenades, hand grenades and automatic weapons. Many of these attacks also killed more than a dozen innocent Iraqi bystanders.

The commander of the battalion, Lieutenant Colonel Rick Carlson, says he does not know for sure why, after months of relative calm, Mosul is suddenly seeing an upsurge of anti-American violence.

But he said he believes much of it is linked to his unit's success in recent months of hunting down top leaders within former Iraqi dictator Saddam Hussein's government and rooting out Saddam loyalists operating in and around Mosul.

"It could very conceivably be they're at a culminating point and they're excessively desperate right now," said Lieutenant Colonel Carlson. "We have scored enormous gains."

In July, soldiers from the 101st Airborne Division, acting on a tip, killed Saddam's two sons in a bloody shootout in a house in a wealthy Mosul neighborhood.

Since then, Lieutenant Colonel Carlson says many Iraqis have come forward with information about other senior members of the former government, who are believed to be offering money and supplying arms to poor locals to carry out attacks against coalition forces.

"I don't think there are a lot of individuals, at least in this area, that have said, 'Well, I'm going to take up guns.' The one thing we clearly know and understand is that poor people have got to eat and if someone says, 'Hey, I'll give you $50 to throw this grenade at coalition forces,' he's going to take the $50 in order to feed his family," he said.

Relying on local intelligence, U.S. troops have been focused on arresting the people behind the money offers as a way to decrease the number of attacks.

On Sunday, the battalion received a solid tip that a former two-star general on the division's most wanted list is in Mosul after months of being in hiding.

The general, Abdullah Ahmed al-Sabawi, is suspected of providing large amounts of cash and arms to locals to conduct terrorist activities. He has eluded capture at least a dozen times.

A pre-dawn raid is planned to arrest him at his home.

To the soldiers' surprise, the occupants of the house open the door without resistance. After a thorough search of the house and several hours of interrogation, a man believed to be the general is arrested.

The arrest provides some relief to the soldiers, but their task of securing the city is far from over.

Lieutenant Colonel Carlson says his men also face violence from foreign Islamic militant fighters, who are trying to establish a base in Mosul.

The city is close to the Syrian border, where hundreds of militants are believed to have crossed into Iraq since April.

Taxi driver Ibrahim Khalil Ismail shakes his head at the possibility that Mosul could remain volatile and dangerous for the foreseeable future.

Mr. Ismail says he just wants to drive his cab and live in peace. "Why won't they let me do that?" he asks.