IRBIL, Iraq — Insurgents targeting Iraqi security forces yesterday killed at least 36 people in four cities, including the Kurdish stronghold of Irbil, which a top government official had described only a day earlier as one of many stable areas of Iraq.

The military also reported yesterday that a U.S. soldier was killed by a roadside bomb near the northern town of Tall Afar.

The bloodiest attack took place in a dusty field behind Irbil's traffic-police headquarters, where a suicide car bomber killed 13 and wounded 100 during police officers' morning workout. In a second attack in the mainly Kurdish town, a suicide bomber killed a local security official and two of his guards as their convoy passed a cemetery.

On Sunday, Iraqi Foreign Minister Hoshyar Zebari had described the city as one of many stable areas in Iraq.

In recent days, American and Iraqi officials have declared that massive raids on insurgents in Baghdad and west of the capital had been successful.

In the capital, attacks began just before dawn when two car bombs targeted Iraqi special forces in the Rissalla neighborhood, killing two people. In what appeared to be a highly coordinated assault, 30 insurgents tried to storm the Bayaa police station using mortars, rocket-propelled grenades, a car bomb and small-arms fire.

In a fierce gunbattle with Iraqi commandos, police officers and U.S. forces, 10 insurgents were killed and 20 captured, according to the U.S. military. Four Iraqi security officers were killed.

The violence — including coordinated car bombs, mortars and heavy machine-gun fire — underscored the apparent strategy of insurgents in Iraq: As U.S. and Iraqi commanders hit hard in one region, insurgents hit back in another. The U.S.-led assaults so far don't appear to have seriously undermined the long-term ability of insurgents to move forces and launch attacks.

U.S. and Iraqi forces in far western Iraq conducted a fourth day of search-and-destroy operations aimed at insurgent activity on the Syrian border and at preventing foreign fighters from being smuggled into Iraq.

The operation by U.S. Marines and Iraqi soldiers, called Operation Spear, has focused on the town of Karabilah, which was entirely controlled by Marines, residents said yesterday.

In interviews, Karabilah residents said U.S. warplanes conducted airstrikes on three neighborhoods where guerrillas loyal to the group al-Qaida in Iraq were operating. More than a dozen houses, four mosques, two schools, a medical center and dozens of shops were destroyed, witnesses said.

"I hope this will be the end for those Arab terrorists whose main aim is to destroy the country," said Hamed Saeed, 40, a government employee. "I hope this will be a lesson to the people who also are helping and hiding them in their houses."

A leading political party representing Sunni Muslims, however, said in a statement that Operation Spear had caused immense suffering for residents of Qaim, a town just west of Karabilah on the Syrian border. "What is going on now in Qaim and its suburbs is a new massacre that the occupier is conducting against people in the name of fighting terrorism and the terrorists," according to the statement by the Iraqi Islamic Party.

Millions of Baghdad residents

without city water for 2nd day

With temperatures reaching 100 degrees, millions of Baghdad residents went without city water for a second day yesterday following a rocket attack on a water pipeline, and city officials said the shortage could stretch into a third day.

Amir Ali Hasson, a spokesman for the Baghdad mayor's office, said repairs would be completed by late today. Insurgents have frequently hit infrastructure in a bid to destabilize the government.

Compiled from Los Angeles Times, The Washington Post, The Associated Press and Knight Ridder Newspapers