Over the weekend, US troops opened fire near a checkpoint south of Baghdad after their convoy was hit by a roadside bomb, and a hospital official said Sunday at least eight people were killed.

Brig. Amer Ali Nayef and his son, Lt. Khalid Amer, were killed yesterday by machine-fun fire sprayed from two cars driving parallel to the chief's as he and his son drove to work, police said.

In a separate attack, a suicide car bomb exploded in the courtyard of a police station in southern Baghdad Monday, killing at least four officers and injuring 10 others, police and witnesses said. A fake police car packed with explosives was used in the attack.

The explosion took place at 8 a.m. in the Zafarniyah district, police commissioner Abdul Khaleq Hussein said. Witnesses said the explosion happened as policemen were changing shifts. An Associated Press photographer saw a number of bodies inside the courtyard that was cordoned off by police.

The killings were the latest in a series of attacks against ranking Iraqi security force officials and policemen on the eve of a landmark Jan. 30 election that insurgents are trying to disrupt. Last week, gunmen killed the governor of Baghdad, Ali al-Haidari, and six of his bodyguards.

Meanwhile, two US soldiers were killed and four wounded yesterday when a bomb blast ripped through an Abrams tank in southwestern Baghdad, the US army said.

"A patrol reported striking an improvised explosive device, destroying an Abrams tank. The wounded were evacuated to a military medical treatment facility," the 1st Cavalry Division said in a statement in Baghdad.

Another US Marine was killed in action on Sunday while conducting security and stability operations in the restive Al-Anbar province in western Iraq, the army said in a statement.

The US army statement, released Monday, gave no details of the deceased "pending next of kin notification".

The Ukrainian troop toll from an accidental bomb explosion in Iraq climbed to eight yesterday, after the defense ministry said one of the men wounded in the blast died in hospital.

In other violence Sunday, a US soldier assigned to Task Force Baghdad was killed by a roadside bomb, and a Marine was killed in action in the volatile Anbar province.