BAGHDAD, Iraq — Iraqi insurgents set off bombs and fired rocket-propelled grenades and automatic weapons at military convoys, checkpoints and police patrols in a spate of violence yesterday that killed 33 people and wounded dozens.

Al-Qaida in Iraq, led by Jordanian militant Abu Musab al-Zarqawi, purportedly claimed responsibility in an Internet statement for much of the bloodshed that killed 15 people in and around Baqouba, 35 miles northeast of Baghdad.

The assaults included a car bomb, three roadside bombs and small arms attacks on three checkpoints, one of them just south of Baqouba in Muradiyah, said police Col. Mudhafar al-Jubbori

A car bomb also killed 12 people in Balad, southeast of Baqouba.

In Baghdad, gunmen killed two police officers and wounded a third, while two civilians were killed when a roadside bomb targeting a joint U.S.-Iraqi military convoy exploded in the Baghdad neighborhood of Amiriyah.

In Baghdad's Doura district, gunmen killed Mahmood Khudier, a former Iraqi army officer, while a man was killed in a mortar attack in Qaim, near the Syrian border, hospital and police officials said.

British plane downing still a mystery

LONDON — Military officials yesterday ruled out sabotage and engine failure in the crash of a British transport plane Jan. 30 in Iraq. Ten people died in the crash.

An interim report by the Royal Air Force board of inquiry excluded a range of other possible explanations, including lightning, collision with another aircraft or cargo exploding in the crash of the Hercules C-130 transport north of Baghdad.

But the panel did not rule out the possibility that the Hercules, which was on an administrative flight between Baghdad and a U.S. air base at Balad, may have been shot down by guerrillas with a surface-to-air missile.

On Feb. 9, Air Force Lt. Gen. Lance Smith, the deputy commander of U.S. Central Command, said he believed the British aircraft was downed by hostile action rather than by a mechanical problem.

He had also suggested the possibility of sabotage.

The death toll of 10 was the highest for any single incident suffered by the British military in Iraq since the war was launched in March 2003.

Judge won't dismiss Abu Ghraib charges

FORT HOOD, Texas — A military judge refused yesterday to dismiss any of the charges against Spc. Sabrina Harman, an Army prison guard accused of humiliating Iraqis held at Abu Ghraib.

Harman, who appears giving a thumbs-up next to an Iraqi corpse in one of the most notorious photographs from the Baghdad prison, could become the second person to stand trial in the scandal when her court-martial begins May 12. Pvt. Charles Graner Jr. was convicted in January and sentenced to 10 years.

Harman, a 27-year-old reservist and former pizza shop manager from Lorton, Va., is accused of writing "rapist" on the leg of one prisoner and forcing another to stand on a box with wires in his hands and telling him he would be electrocuted if he fell. Harman is also accused of taking photographs of a group of naked detainees.

Her legal team tried to get the photograph-related counts dismissed, arguing that the prisoners were not harmed because they were wearing bags on their heads.

Assembly may meet outside Green Zone

BAGHDAD, Iraq — Despite the continuing violence, a top Shiite politician said yesterday that the newly elected national assembly, when it convenes for the first time March 16, might not meet in the U.S. protected Green Zone in Baghdad.

Ahmad Chalabi, who met yesterday with members of the United Iraqi Alliance, a cleric-led Shiite group that won 140 seats in the 275-seat assembly, said some Alliance members don't want to meet in the Green Zone "under foreign arms." The Green Zone is guarded, and partly occupied, by U.S. forces.

"Iraqis must see that this assembly is acting differently from the (current) government," Chalabi said. "They must be seen to be elected and representing a sovereign people."