TOKYO - Japanese Prime Minister Yukio Hatoyama said Tuesday his government was striving to secure the release of a Japanese engineer kidnapped by tribesmen in Yemen "at any cost."

"We are making a strong effort to resolve the case through negotiations between the two governments. We want to resolve it at any cost," Hatoyama told reporters.

He said the Japanese citizen was not known to have been hurt.

Gunmen kidnapped the Japanese engineer in Arhab, a region northeast of the Yemeni capital Sanaa, on Sunday to seek the release of a fellow tribesman detained by the authorities, a Yemeni official said on Monday.

The kidnapped engineer was identified only as a member of a Japanese aid agency operating in Yemen.

Yemeni tribes habitually kidnap foreigners to try to put pressure on local authorities. More than 200 foreigners have been seized during the past 15 years, with most being freed unharmed.

Two Japanese women were released unharmed in May last year after briefly being taken hostage by Yemeni tribesmen.