BAGHDAD, Iraq - Attackers gunned down a police officer heading to work Saturday in the oil-rich city of Kirkuk, then bombed a funeral procession carrying his corpse, killing three other policemen and injuring two, officials said.

The attacks came on the second anniversary of the U.S. invasion on March 19, 2003, and are typical of the violence that has become commonplace in Iraq.

The attackers sprayed automatic-weapon fire from a vehicle, killing the policeman as he made his way to the station house early Saturday, police Capt. Ahmed Shinrani said. Hours later, a roadside bomb hit mourners and security forces transporting the corpse for burial.

"This is a criminal act. The mourners were doing a religious duty. I don't understand how someone could blast a funeral," wailed Allaa Talaban, wife of one of the officers killed in the blast in Kirkuk, 180 miles north of Baghdad.

The Kirkuk attacks came as unidentified assailants in Baghdad killed police Commissioner Ahmed Ali Kadim as he traveled to his office in the Doura neighborhood of the capital, said Falah Al-Mohammadawi, an investigator in the precinct.

Also Saturday, a suicide attacker detonated a car bomb, targeting a U.S. military patrol on a highway three miles northwest of Ramadi, a city 70 miles west of Baghdad in the restive region known as the "Sunni Triangle," Sgt. Laith Ismael of the Iraqi police said.

The U.S. military said in a statement the car bomb "detonated prematurely, before it could reach the patrol." The statement made no mention of casualties.

U.S. and Iraqi forces also clashed Friday with gunmen in Ramadi after militants attacked a government building. No casualties were reported.

The Sunni Arab-led insurgency routinely attacks U.S. and other international troops while also targeting local security forces and officials they consider to be the Americans' collaborators.

Iraqis kept up protests Saturday against a Jordanian man they believe carried out a suicide bombing that killed 125 people in Hillah on Feb. 28. "No, no to terrorism," chanted about 200 people in Baqouba, 35 miles northeast of Baghdad.

The Jordanian daily Al-Ghad had reported that the man, Raed Mansour al-Banna, carried out the attack, the single deadliest of the Iraqi insurgency. The paper later issued a correction, however, saying it was not known where in Iraq al-Banna carried out an assault.