Sheik Hezam al-Amrani, whose tribe was involved in the abduction, said that the 24 abducted medical workers were freed after the kidnappers received assurances through mediators that their demands would be met.

Saada, where the medical workers were abducted, is where in 2004 tribesmen led by members of the al-Houthi family began an intermittent uprising against the government.

The tribesmen cited alleged economic and religious discrimination as the reason for their armed campaign.

Tribesmen often kidnap Western tourists in Yemen to press the government into providing better services and living conditions.

Most foreigners abducted in Yemen are released unharmed, but in 2000 a Norwegian was killed in crossfire and in 1998 four Westerners were killed during a botched attempt to free them.