Yemeni authorities say rebels have kidnapped nine foreigners, including women and children, in a mountainous northern region.
Government officials on Sunday accused a Shi'ite militant group of taking a group of seven Germans, a British engineer and a South Korean teacher hostage in the Saada region. The Germans are said to include three children, two nurses and an engineer and his wife.
Yemeni officials say the hostages work for an international aid group at a hospital in Saada, where they say foreigners have been working for 35 years.
There was no immediate claim of responsibility for the kidnapping, but Yemen officials claimed that Houthi militants were responsible.
But the rebel group denied any involvement and accused Yemen authorities of trying to tarnish its image.
Rebels loyal to a Zaidi Shi'ite cleric, Hussein al-Houthi, have been fighting government loyalists in Saada province since 2004.
Seoul confirmed only that a South Korean woman is missing and presumed kidnapped in Yemen.
There was no confirmation of the kidnapping from the German or British governments.
German Foreign Minister Frank-Walter Steinmeier confirmed that seven Germans are missing in Yemen. Steinmeier said a government crisis group has been formed and is in touch with Yemeni authorities.
The reported kidnapping comes just days after tribesmen released 24 medical workers, including foreigners, who were abducted Thursday.
Tribesmen in Yemen often take foreigners hostage to pressure the government on a range of demands. The foreigners are generally released unharmed.