Sana'a, Yemen - A group of armed tribesmen freed two Japanese tourists after holding the women captive for several hours in the north-central Yemeni city of Marib, local officials said.

The women, identified as Keiko Mishima and Endo Shizuko, were released Wednesday after the intervention of tribal dignitaries, the officials said.

"They were handed over to police officials, and they are well," a local official told Deutsche-Presse Agentur dpa by telephone from Marib, some 190 kilometres north-east of the capital, Sana'a.

Security sources said four armed men belonging to the al-Muaili clan of the powerful Abida tribe snatched the two women Wednesday afternoon as they were touring Marib's historical dam, considered one of the engineering wonders of the ancient world.

The abductors wanted to pressure the government to free a detained fellow clansman, tribal sources said.

After they were freed, the two women were taken to a Marib hotel to spend the night and would be transferred to Sana'a early Thursday, police sources said.

Witnesses said police guarding the dam site pursued the abductors and clashed with them. One officer was injured.

The women were among five Japanese tourists visiting the site, a witness told dpa. "They forced them into the vehicle at gunpoint, then drove away," he said.

The kidnappers wanted to press authorities in Sana'a to release a clan member identified as Malik bin Muaili, who is in police custody on suspicion of involvement in an attack on police officers in Marib two weeks ago, tribal sources said.

Police officials said security forces were deployed in a search- and-rescue operation in several areas of Marib after the abduction. An Interior Ministry official said police located the abductors' hideout, security forces sealed off the area and tribal dignitaries mediated an end to the standoff.

Armed tribesmen from impoverished areas of the Arab Peninsula country often take hostages and use them as bargaining chips with the government to press for aid, jobs or the release of detained fellow clansmen.

The most recent kidnapping took place in September 2006 when two armed men from the al-Abdullah clan held four French tourists for two weeks in the south-eastern province of Shabwa. They were sentenced to 12 years in prison.

In January 2006, tribesmen abducted five Italian tourists, including three women, and held them hostage for five days in a mountainous village in Marib. Six of the kidnappers received jail terms of five to 20 years.

The kidnapping of the Italians took place one day after the release of a German diplomat, his wife and three sons by tribesmen who took them hostage for several days in Shabwa.

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.

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