Sana'a, Yemen  - Armed tribesmen abducted two Colombian engineers in south-eastern Yemen Friday in an attempt to press the authorities to release three jailed associates, security sources said.

The sources told Deutsche Presse-Agentur dpa that the kidnappers had intercepted a car carrying the two men and their Yemeni driver and taken them at gunpoint to another vehicle.

The abduction took place as they were driving to work at a giant gas exporting project at the Arabian Sea port of Balhaf in Shabwa province.

Shabwa, some 580 kilometres south-east of the capital Sana'a, has been the scene of several kidnappings of foreigners in recent years.

Police said a search-and-rescue operation was underway.

The officials said the kidnappers were members of a clan demanding the release of a fellow clansman detained by police in connection with criminal offences, including robbery.

Armed tribesmen from impoverished areas of the Arabian peninsula 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.

The latest kidnapping took place in Shabwa on August 12 when tribesmen abducted a French engineer of Algerian origin and held him hostage for one day.

In May, a group of armed tribesmen abducted two Japanese female tourists and held them for several hours in the north-central city of Marib.

In 1998, an Islamic militant group kidnapped 16 Western tourists, four of whom died in a botched rescue attempt by police forces, and in 2000, a Norwegian diplomat was killed in a similar rescue attempt. (dpa)