Car bombs and gunmen killed more than 20 people on Saturday across Iraq, including an American soldier, as the government said insurgency-related violence cost the country's vital oil industry about $6.25 billion in damage and lost revenue last year.

British and Iraqi authorities, meanwhile, confirmed that two foreigners who disappeared two days ago in the southeastern city of Basra were Macedonians kidnapped on their way from the airport to the city center. The kidnappers have demanded a ransom, officials said.

Most of the attacks Saturday were directed against the U.S. military and Iraqi police, with civilians caught up in the violence.

The American soldier died when a roadside bomb exploded near a soccer stadium in eastern Baghdad, the U.S. command said. It was the first death of an American soldier since Tuesday and brought the number of U.S. personnel killed since the Iraq war began in March 2003 to at least 2,273, according to an Associated Press count.

Four Iraqi policemen were killed when a roadside bomb exploded near a fuel tanker on an eastern Baghdad highway, police said. Another bomb exploded elsewhere in east Baghdad, killing three Iraqi civilians and wounding four, police said.

A senior Baghdad police official escaped assassination when a bomb exploded near his convoy in the Karradah district. Brig. Abdul-Karim Maryoush was unharmed but two police escorts died, officials said.

Elsewhere, two more Iraqi civilians were killed in a pair of roadside bombings — one in Saddam Hussein's hometown of Tikrit, 80 miles north of Baghdad, and another in Baqouba, 35 miles northeast of the capital.

Both bombs were intended for police patrols, officials said.

Another bomb in Fallujah, 40 miles west of Baghdad, killed a child and blew off his brother's legs, police said.

U.S. soldiers killed three men trying to plant roadside bombs in Baghdad's notorious Dora neighborhood, police said. At least 10 other Iraqis died in gunfights and ambushes throughout Baghdad, police said.

The U.S. command said American and Iraqi troops found and destroyed 11 roadside bombs and three weapons caches in Baghdad in the past 24 hours. Twenty-nine suspects were arrested, the command said.

In addition, police found the bodies of four men — bound, blindfolded and shot to death — in three separate parts of the Iraqi capital. Their identities were unknown and it was unclear when they died, but they appeared to be victims of reprisal attacks by Shiite and Sunni extremists.

The Interior Ministry has announced an investigation into allegations of Shiite death squads in police ranks after U.S. troops arrested 22 policemen preparing to kill a Sunni Arab last month.

Also Saturday, a government official released figures showing the effects of the insurgency on the country's oil industry, the foundation of Iraq's economy. The industry suffered $6.25 billion in losses in 2005 due to infrastructure sabotage and lost export revenues, Oil Ministry spokesman Assem Jihad said.

Jihad told Dow Jones Newswires that Iraqi oil installations were hit by 186 attacks last year in which insurgents killed 47 oil engineers, technicians and workers as well as about 100 police protecting pipelines and other oil-related facilities.

Most of the sabotage took place in northern oil installations, preventing Iraq from exporting about 400,000 barrels a day that normally pass through pipelines to the Turkish port of Ceyhan.
Iraq currently produces around 2 million barrels per day from its southern and northern oil fields, down about 800,000 barrels from levels before the 2003 U.S.-led invasion.

Violence and attacks against foreign contractors also have had a devastating effect on the economy, driving up security costs and delaying reconstruction projects.

British and Iraqi officials said two Macedonians of Albanian ethnicity were seized two days ago along with a Macedonian woman, who was released. The three work for Ecolog, a German-owned Macedonian company that has a cleaning contact at the Basra International Airport.

A $1 million ransom has been demanded for their release, a company employee said on condition of anonymity because he was not authorized to speak to the media.

More than 250 foreigners have been kidnapped in Iraq since 2003, including Jill Carroll, the American reporter who was abducted Jan. 7 in Baghdad.

On Saturday, the U.S. military announced the release of about 430 male Iraqi detainees over the past few days. Carroll's kidnappers have demanded the release of all women detainees. The U.S. military has said the periodic releases are not related to the kidnappers' demands.

Australia said Sunday it would likely not withdraw its troops protecting Japanese reconstruction teams in Iraq even if the Japanese leave.

Defense Minister Brendan Nelson said if the Japanese humanitarian effort stayed beyond May, Australians would continue to guard them, but if they left, Australian forces could redeploy elsewhere in southern Iraq.

Australia has about 1,320 troops in Iraq and the Middle East, including around 460 soldiers guarding the Japanese in the southern province of al-Muthanna.