The U.S. Embassy in San'a says it doesn't have any information about the kidnapping.
Security officials, a taxi driver and tribesmen say the two -- a man and a woman
-- were seized Monday as they were traveling west of the capital in al-Hudaydah province.
The officials spoke on condition of anonymity because they aren't authorized to speak to the media.
Taxi driver Mohammed Saleh, who was driving the two, says six gunmen stopped them on the road and took them to al-Hamra village. Al-Sharda tribesmen say the hostages are "guests" in their village.