BAGHDAD, Iraq -- As Iraqi leaders Sunday trumpeted a swift victory in Fallujah, insurgents pressed their claim on the northern city of Mosul, which is fast becoming Iraq's newest front.

An outbreak of rebel attacks on police stations and government buildings has paralyzed parts of the city. Corpses have been splayed on city streets. Police have said they fear going back to their jobs.

Families are fleeing en masse. Insurgents have assured city bureaucrats that it is safe to return to work, that rebels will secure city streets.

"The situation is very bad here, and it's getting worse," said Abdul Wahab Ibrahim, who is fleeing with his family. "People are afraid that the same thing that happened to Fallujah will happen to Mosul."

The violence in Mosul serves as a troubling postscript to the military success of the weeklong assault on insurgents in Fallujah, described Sunday by Maj. Gen. Richard Natonski, who designed the ground attack, as a "flawless execution of the plan we drew up."

While the U.S.-led force has been fighting through Fallujah, once regarded as the symbol of rebel resistance in Iraq, a wave of violence has swept through several cities across central and northern Iraq, killing dozens of people and wounding scores more.

On Sunday, insurgents in Mosul raided two police stations and torched the governor's house. Gunbattles erupted in the main market of the northern town of Beiji and outside the Polish Embassy in Baghdad. Saboteurs set ablaze four oil wells near Kirkuk, and an oil pipeline was burning after an attack Saturday night in Taji, north of Baghdad.

The attacks have given currency to insurgents' warnings that no matter what happens in Fallujah, the fight against the American occupation of Iraq will continue and even escalate as national elections in January approach.

But Iraqi leaders and top U.S. commanders have expressed confidence that they can snuff out flare-ups of insurgency violence where and when they occur.

"This is all Iraqis against terrorists," said Prime Minister Iyad Allawi during a visit to Nasiriyah over the weekend. "We are going to keep on breaking their back everywhere in Iraq. We are not going to allow them to win."

That battle to crush the insurgency had to begin in Fallujah, U.S. and Iraqi leaders decided. Fallujah's guerrillas, largely a mix of foreign fighters, Sunni Muslim radicals and Saddam Hussein regime loyalists, put up fierce fighting when Marines launched a major offensive in April. U.S. officials ordered the offensive after the killings and mutilations of four American contractors in the city in late March.

Marines abandoned the offensive after Iraqi leaders complained about the devastating toll the assault was taking on Fallujah civilians - an assertion U.S. leaders disputed.

Fallujah soon became a nerve center for insurgency operations, many of them masterminded by militant Abu Musab al-Zarqawi. The Jordanian, who recently renamed his Tawhid and Jihad group al-Qaida in Iraq, has been blamed for many of the kidnappings, beheadings and suicide car bombings in Iraq in recent months.

During the assault on Fallujah, U.S. troops came upon what appeared to be slaughterhouses where hostages kidnapped by al-Zarqawi loyalists and other insurgents apparently were held captive and murdered. Black clothing worn by kidnappers was found. Over the weekend soldiers found in one of the houses the passport of Shosei Koda, the Japanese tourist recently kidnapped and beheaded.

Planning for the offensive began in September, U.S. Marine commanders told The Associated Press. Unlike the assault in April, when 2,000 U.S. troops were deployed, last week's assault involved up to 12,000 U.S. troops and 3,000 Iraqi soldiers.

In the days before the assault, U.S. air and artillery strikes pounded insurgent fortifications and safehouses. Military leaders also faked several invasions on the south and east edges of the city to divert concentrations of insurgents from the north, where the actual assault took place, Natonski said.

U.S. forces have spread through the city, but it could take several more days before the area is secured, U.S. officials said.

"The perception of Fallujah being a safe haven for terrorists, that perception and the reality of it will be completely wiped off before the conclusion of this operation," said Lt. Gen. John Sattler, commander of the 1st Marine Expeditionary Force.

But U.S. military leaders have acknowledged that many fighters escaped before the fighting began, including al-Zarqawi. And as the assault intensified, so did attacks outside Fallujah.

Especially troubling has been the brazenness of the attacks in Mosul, a northern city of about 1.7 million with a mix of Arabs, Kurds, Assyrians and Turkmens.

Last week, insurgents hit nine police stations, looting flak jackets, rifles and arms from several of the stations. Other stations were burned. Two more stations were attacked Sunday, leaving at least six Iraqi troops dead.

Insurgents have roamed Mosul's streets freely, grenade launchers slung over their shoulders.

The U.S. military said Sunday that the Iraqi interim government remains in control of the city and that "resistance is sporadic." But an Iraqi reporter who drove through Mosul and neighboring Tal Afar over the weekend said masked gunmen in sections of both cities are maintaining a strong presence and have begun setting up checkpoints.

A host of other cities and villages in restive Sunni Muslim regions of northern and central Iraq have seen escalations in assassinations of government officials, car bombings and ambushes since the Fallujah offensive began.

Residents of the capital's al Dora neighborhood were horrified last week when insurgents used a quiet, residential side street to launch a rocket-propelled grenade attack on Iraqi police cars nearby. The attack triggered a fierce firefight that riddled the neighborhood with bullet holes.

"Bullets were coming in every direction," said Oday al Jaburi, a local pharmacist. "Most of the windows were smashed."

Just as disturbing has been the Fallujah assault's impact on Iraq's political scene, with the elections less than three months away. An influential Sunni Muslim clerics association has called for a boycott of the election. The non-participation of Sunni Muslims could seriously undermine the election's legitimacy and push the country to the brink of civil conflict.

On Sunday, hundreds of Iraqis demonstrated in the Sunni Triangle city of Buhriz to protest the assault and Allawi's government. Some carried banners calling Allawi a "thug." Others chanted, "Allawi, Fallujah will be your tomb."

Whether the Fallujah offensive dims hopes for free and fair elections in January, or lays a foundation for them, will depend on how quickly order is restored and reconstruction starts, Iraqi and U.S. leaders say. Most Fallujans fled the city before the assault began. When they return, they will find a broken, battered city in dire need of wholesale reconstruction.

The U.S. military has teams of contractors and civil affairs specialists waiting to embark on a host of infrastructure projects, once the city is safe enough for construction work to begin.

By Alex Rodriguez
Chicago Tribune

Chicago Tribune correspondent James Janega in Fallujah and news assistants in Mosul and Baghdad contributed to this report.