-- Insurgents launched attacks in the capital and parts of northern Iraq on Monday, including a suicide car bombing in the northern city of Irbil that killed at least 16 traffic police officers and wounded more than 100 others.

Dozens of traffic officers were lined up for morning training in an exercise yard in Irbil, 200 miles north of Baghdad, when "the bomber drove his car in and blew himself up among them," said Irbil's mayor, Nawzad Hadi.

One wounded policeman, Faryard Khorsheed, 22, said: "I couldn't run away. I saw dozens of dead bodies and pieces of flesh -- all belonging to my colleagues -- and the whole area was full of the smell of blood and burned flesh."

A bomb detonated on a road near the town of Tuz Khurmatu, 115 miles north of Baghdad, as an Iraqi army convoy passed by, killing three soldiers and wounding two, said police Col. Abbas Mohammed.

In the capital, insurgents struck a handful of targets in the early morning hours, employing car bombs, roadside explosives and small-arms fire, according to U.S. and Iraqi officials.

The attacks came one day after a suicide bomber killed 23 people, including several police officers, in a restaurant just outside Baghdad's fortified Green Zone. On Saturday, U.S. and Iraqi military commanders had noted a marked decrease in such attacks during Operation Lightning, a four-week-old security crackdown in and around the capital.

U.S. and Iraqi forces in far western Iraq, meanwhile, 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 Monday was entirely controlled by Marines, residents said.

A Marine spokesman said in a statement that searches uncovered three car bomb factories in western Karabilah. A total of 17 car bombs were found, including a tractor trailer, a dump truck and a van rigged with explosives, which were destroyed on the spot by a Marine tank.

Over four days, 33 buildings were damaged or destroyed during combat operations, according to the statement, which added that only buildings occupied by insurgents or foreign fighters were fired on.

In interviews, Karabilah residents said U.S. warplanes conducted airstrikes on three neighborhoods where guerrillas loyal to the group al Qaeda 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.

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

In the heaviest of Monday's clashes in Baghdad, gunmen fired on a U.S. military patrol at 5:30 a.m. near a police station in the southwestern corner of the city, then detonated a car bomb when Iraqi police and soldiers responded, according to the U.S. military and the Iraqi Defense Ministry. The attackers then trained mortars and machine guns on the police station in a sustained barrage that ended with the arrival of more U.S. ground forces and air support.

The U.S. military reported no American casualties in the clash but said four policemen and one Iraqi soldier were killed. The Defense Ministry said, however, that there were no Iraqi casualties. The conflicting reports could not immediately be reconciled.

Elsewhere in Baghdad, a roadside bombing in the Mansour district killed four police officers, and a gunfight between police and insurgents left one Iraqi dead and 15 wounded, according to the Defense Ministry. Two car bombs exploded outside a police commando headquarters in Nisoor Square but caused no casualties, the ministry said in a statement.

In a Web posting, the insurgent group Ansar al-Sunnah asserted responsibility for attacking a convoy as it left a base near Ramadi, 60 miles west of Baghdad, killing a foreign contractor and six of his Iraqi guards and capturing two others, the Associated Press reported.

Although its claim could not be immediately confirmed, the statement, posted on a Web forum often used by Ansar al-Sunnah and other militant groups, identified the contractor as Japanese and included pictures of his identification cards. These named the contractor as Binkumar Gurung, who worked for the American-Iraq Solution Group, a firm contracted by the U.S. Defense Department. The statement was dated Sunday but it did not say when the attack took place.

Iraqi police gather around a bomb blast crater in the yard of a Baghdad police station where at least eight officers and one baby died, officials said.