Three US soldiers killed in a roadside bomb blast on Wednesday. The soldiers were on patrol when the bomb exploded south of Baghdad.

A fourth soldier died from wounds sustained in a small-arms fire attack in the capital's southwest, the military said. A US Marine was fatally wounded during combat near the western city of Fallujah.

All five US servicemen were killed Wednesday, the military said.

A US military spokesman said fighting began around 1:00 am (2200 GMT Wednesday) when the coalition forces came under attack during a raid in the poor, predominantly Shia Baghdad district.

"The coalition forces conducted a raid in Sadr City to search for a known terrorist from Ansar al-Sunnah group," the spokesman told AFP.

"After conducting the raid one of the helicopters of the coalition forces came under fire from some men on a nearby rooftop following which another helicopter of the coalition forces returned fire to eliminate the threat in which four individuals were killed."

He did not say whether the four were members of the Mehdi Army, though an interior ministry official said the fight was between US forces and the Mehdi Army.

The official added that a woman was killed in the fighting.

Sadr's militia and the US military have often clashed in the past, most dramatically in August 2004 when the fiery cleric waged a bloody rebellion in the Shia holy city of Najaf in which hundreds of his men were killed.

In other violence, a high-ranking official at the industry ministry, Mary Hamza al-Rubai, was kidnapped on her way to work. Two cars filled with gunmen stopped her car, released her driver and took her away.

The interior ministry also reported that gunmen in a large SUV, of the kind used by foreign security details, opened fire on a commuter microbus south of Baghdad, killing two and wounding seven.

On Wednesday, two Iraqi journalists were snatched after leaving a press conference at the headquarters of the Sunni Iraqi Islamic Party.

Gunmen attempted to assassinate the police intelligence officer responsible an area south of Basra, but only succeeded in killing his driver.

In a separate incident, insurgents attacked an oil storage facility near the northern city of Kirkuk setting off a massive blaze, an official with the Northern Oil Company said.

He said the attack occurred at 3:00 am (midnight GMT), adding the blaze was still continuing as the sun rose.

The US military said two children died in the town of Hit during a gunfight between security forces and insurgents on Wednesday.

It said insurgents attacked an Iraqi-US patrol in which one Iraqi soldier and four other civilians were wounded.

A number of bodies were discovered around the country on Thursday, including two in Nabaie north of Baghdad that were believed to be among an ill-fated expedition of police hopefuls from Samarra in mid-January.

At least 60 young men had been returning from Baghdad after failing to be accepted by the police academy when their bus was stopped by insurgents and they were taken off into the desert.

So far, police and medical sources have identified 39 corpses from the group, mostly in the region around Nabaie.

The hospital in Samarra also reported receiving the body of a civilian shot in the head, with no information about what happened.

The body of a policeman kidnapped Wednesday was found in an eastern suburb of Baghdad, riddled with bullets, while the interior ministry reported another seven bodies found at the edge of Sadr City.