A Dutch couple living in Yemen disappeared in Sanaa, police said on Saturday, with press reports saying they had been kidnapped.
"The police commissariat in Sanaa learned on Saturday of the disappearance a few days ago of a Dutchman and his wife," a security official said on condition of anonymity.
Press reports said the couple, who have not been named, had not been seen for three days, had been abducted.
Daily Al-Yemen Al-Youm reported that "unknown men kidnapped" the couple, without giving details.
Western sources said the pair were teaching at the Lebanese International University in Sanaa, and that the wife was also a journalist working for a radio station in The Netherlands.
Another source close to the couple spoke of last seeing the woman three days ago, and saying they had probably been kidnapped.
The two had not been seen at the university since Tuesday, some of their students said.
It was not possible to contact the Dutch embassy on Saturday.
Hundreds of people have been abducted in Yemen in the past 15 years, nearly all of them later freed unharmed.
But Al-Qaeda has also seized foreigners in the country, including a Saudi diplomat, Abdullah al-Khalidi, who is still being held by the network after being kidnapped in March 2012 in Aden.
Al-Qaeda militants also are holding a South African couple abducted in May in the central city of Taiz, a security official said on June 6.
In early May, members of a southern tribe freed three Red Cross employees, including a Swiss and a Kenyan, along with two Egyptian hostages, following tribal mediation.
Most kidnappings of foreigners are carried out by members of Yemen's powerful tribes who use them as bargaining chips in disputes with the central government.