Baghdad, Iraq ? Attackers killed nine people, including four women headed to jobs at a U.S. military base and two American soldiers, in an outburst of violence. South of the capital, the security chief of Spanish troops in Iraq was shot in the head during a raid.

Two Iraqi policemen were killed Thursday and three others were wounded when gunmen fired on a police checkpoint between Fallujah and Ramadi, two insurgency hotspots west of Baghdad.

The attack occurred along the same road where the day before, assailants firing from a speeding car killed four Christian women and wounded six other people in a convoy headed for the U.S. military base at Habaniyah, 50 miles west of the capital.

Elsewhere, two U.S. soldiers were killed and another wounded during a rocket and mortar barrage late Wednesday on an American camp near Baqouba, 35 miles northeast of Baghdad. American troops returned fire, damaging a house, witnesses said.

The deaths of the soldiers brought to 505 the number of American service members who have died since a U.S.-led coalition launched the Iraq war March 20. Most of the deaths have occurred since President Bush declared an end to active combat May 1.

In Madrid, the Spanish Defense Ministry said the security chief for Spanish troops in Iraq was shot and seriously wounded Thursday during a raid against suspected insurgents south of Diwaniyah, headquarters of the 1,300-member Spanish military force in Iraq.

Civil guard commander Gonzalo Perez Garcia was rushed to a U.S. military hospital in Baghdad, where he was in critical condition.

Ten Spaniards have died in Iraq since August, including seven intelligence agents killed in an ambush in November.

In Basra, Iraq’s second-largest city, the 23-year-old son of a former senior official from Saddam Hussein’s Baath party was slain Thursday by an unidentified attacker.

The attacks in the Fallujah area followed a period of relative calm there since the arrest Jan. 11 of Khamis Sirhan al-Muhammad, a former Baath party official.