Iraqi militants claimed on Monday that they took a Japanese hostage after ambushing a convoy of foreigners and Iraqi troops in western Iraq. The man's employer confirmed he and other employees were missing from the attack. (Xinhua/Reuters)

An Iraqi militant group linked to the al-Qaida terror network said on Monday that it had kidnapped a Japanese after killing four other foreign contractors.

In a statement posted on the Internet, the Ansar al-Sunna Army identified the hostage as Akihiko Saito, an operation manager working with a security company in Iraq.

Photocopies of two of his documents were displayed on the website.

The group claimed that its members had ambushed a convoy carrying Saito and four other foreign contractors along with 12 Iraqi security guards.

"The mujahedeen (holy fighters) obtained information that the convoy had left the US military base of Al-Assad before they set the ambush," said the statement.

The cars came under attack near Hit, 170 km northwest of Baghdad, according to the statement, which could not be verified.

The group also said all the travellers except the Japanese were killed in a fierce battle before US helicopters were called in.

It did not explain why they chose to spare the life of Saito, but said it would provide documents of the dead, whose bodies could have been recovered by the US forces.

Saito was "severely injured during the fighting," the statement added.

A young Japanese backpacker was abducted late last year and was later found beheaded in Baghdad after Tokyo refused to withdraw its troops from Iraq as the kidnappers demanded.

The al-Qaida allied group led by Jordanian militant Abu Mussabu al-Zarqawi was behind the killing.

Japan has some 500 troops deployed in Samawa, 280 km south of Baghdad.

Ansar al-Sunna has claimed some of the deadliest attacks in Iraq. Last year, the group said it had kidnapped and slayed 12 Nepalese working with the US forces.

US and Iraqi security officials believe that the militant group has kept a level of cooperation with other militant groups in Iraq and may be hiding in the western desert area near the Syrian border.