The aid group Médecins Sans Frontières (Doctors Without Borders) said on Monday it had lost contact with two of its employees in Yemen.
The workers - a German and a Myanmar national - were in Yemen's central Marib region, the charity said in a statement emailed to Reuters, adding that it would not share further details out of concern for the workers' safety.
Earlier this month, the U.N. announced the release of five of its employees who had been held for 18 months after being kidnapped by al Qaeda militants in Yemen's southern Abyan region.
