Sana'a, Yemen  - Yemeni tribesmen holding a Dutch couple hostage said on Wednesday they would release them if two provincial police chiefs are put on trial over a shootout last year in which four fellow clansmen were hurt, a municipal official said.

Jamil Shuraih, the secretary-general of the Bani-Dhabian district, where the Dutch hostages are being held, said the abductors also demanded financial compensation for injuries suffered by their relatives during the gunfight.

Shuraih told the German Press Agency dpa that the clash took place between members of the Al Seraj clan and police forces four months ago at a checkpoint in Marib province, around 170 kilometres north-east of Sana'a.

"We began contacts with the kidnappers, and they insisted that the police superintendent of Marib and the commander of central security forces in the province stand trial," Shuraih said.

He said the kidnappers had accused the two officials of ordering an attack on their fellow men.

Six armed tribesmen intercepted the Dutch man and his wife as they were driving in a southern Sana'a suburb on Tuesday, and took them at gunpoint to a mountainous area around 80 kilometres east of the capital city.

Shuraih said the hostages were Dutch man, who works as an expert at a water project funded by the Dutch government in the southern Yemeni city of Taiz, and his wife.

The kidnapping is the third involving foreigners in Yemen this year.

On January 18, tribesmen abducted a German oil expert in the south-eastern Yemeni province of Shabwa and released him two days later. The kidnappers demanded the release of a jailed fellow tribesman.

On January 3, tribesmen seeking the release of a jailed fellow clansman took a South African tourist and her two sons hostage for one day in the southern province of Abyan, but later released them unharmed.

Disgruntled tribesmen from impoverished areas of Yemen often take hostages to use as bargaining chips to press the government for aid, jobs or the release of detained fellow clansmen.

More than 200 foreigners have been kidnapped in Yemen since 1991. Almost all were released unharmed after mediation involving tribal leaders. (dpa)