British and Iraqi forces raided homes in southern Iraq on Monday and arrested four suspects in the kidnapping of four American security guards and their Austrian co-worker, an official said.

The raid, which began late Sunday and ended early Monday morning, took place in Zubair, a mostly Sunni-Arab enclave about 20 miles south of Basra, Capt. Tane Dunlop, the British military spokesman, told The Associated Press. Most of Britain's 7,200 soldiers in Iraq are based in the city.

On Sunday, Iraqi police showed the media 200 suspected insurgents they had arrested the night before while raiding several areas north of Basra, which is 340 miles southeast of Baghdad.

Both raids failed to find any of the hostages in southern Iraq, a mostly Shiite region.

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The four American security guards and their Austrian co-worker have been missing since Thursday when a large convoy of trucks being escorted by their Crescent Security Group company was hijacked on a highway near Safwan, a largely Sunni Arab city of 200,000 people on the Kuwait border.

Suspected militiamen dressed in Iraqi police uniforms ambushed the convoy, taking 19 of its trucks and 14 hostages: the five security guards and nine foreign truck drivers who were later released.

Officials at Crescent Security Group Inc. have refused to comment on the five hostages since Saturday, but the company issued a statement on its Web site saying they remain unaccounted for.

Islamic Companies, a previously unknown group, claimed responsibility for the kidnapping, according to an Iranian-run Arabic-language satellite news station. It said the group released a videotaped message saying it was holding the five men and demanded the withdrawal of U.S. forces from Iraq and the release of all prisoners being held there.

U.S., British and Iraqi forces have all spent time searching for the five captives.

Austrian officials have not confirmed the name of the missing Austrian, describing him only as a 25-year-old former soldier from the province of Upper Austria.

Two of the American captives have been identified: Jonathon Cote, 23, a native of Getzville, N.Y., and Paul Reuben, 39, a former police officer from a suburb of Minneapolis, Minn.

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