-- Attacks on police forces and other targets Friday night and Saturday killed at least 20 Iraqis north and west of the capital, while the U.S. military announced that the confirmed death toll in Thursday's suicide bombing of a vehicle filled mostly with female Marines had risen to four, three of them men.

In the first attack on police, six officers were killed Friday night when a large band of insurgents assaulted a police station near Ramadi, about 60 miles west of Baghdad, according to police Maj. Hussein Jasim Mohammed.

Mohammed and local residents said that more than 30 attackers, including Iraqis and foreigners, struck the headquarters of the Highway Protection Department at about 7 p.m. with rifles, machine guns and grenades.

While insurgent groups have mounted some operations in large numbers since February, the vast majority have been ambushes by small bands, suicide bombings and the detonation of hidden bombs.

An announcement posted at a mosque in Ramadi, the capital of violent Anbar province, claimed responsibility for Friday's action in the name of al Qaeda in Iraq, a radical Islamic guerrilla group led by Abu Musab Zarqawi, a Jordanian, that has carried out scores of attacks on security forces and civilians. The group asserted in the announcement that the policemen were "apostates and we decided to execute them."

In the second attack on police, a suicide car bomber blew himself up Saturday outside an officer's home in Samarra, 60 miles north of Baghdad, killing at least nine people, according to police and hospital officials quoted by the Associated Press. The apparent target, Lt. Muthana Shaker, was not injured, police said.

In Baghdad's battered Shuala district, five civilians were killed and seven were wounded when three mortar shells struck a cafe Saturday night, the Associated Press quoted police as saying.

The cafe had been targeted several times; a triple bombing at the site Wednesday night killed 15 people.

The U.S. Marines confirmed the deaths of two male Marines who had been listed as missing after a suicide bombing Thursday night in Fallujah. That raised to four the number of Marines killed in the attack on a vehicle that was carrying female Marines who perform security checks on women passing in and out of Fallujah, a city in Anbar province, 35 miles west of Baghdad.

One of the four dead Marines was a woman, as were 11 of 13 Marines wounded in the bombing. One Marine and one sailor were still listed as missing, the Marines said in a statement.

Meanwhile, commercial flights in and out of Baghdad's international airport were halted indefinitely when the private security firm guarding the facility went on strike in a contract dispute with the Iraqi Transportation Ministry.

Iraqis gather at the wreckage of Lt. Muthana Shaker's home in Samarra, where a suicide car bomber slammed into a wall, killing nine.