Mozambican carrier LAM is trying to ascertain the location of an aircraft which had been operating a service to Angola.
It apparently disappeared while conducting flight TM470 from Maputo to Luanda, with 28 passengers and six crew.
The flight departed at 11:26, the airline says, and had been due to arrive at 14:10.
LAM says it has information the aircraft "landed" at Rundu in northern Namibia.
But the carrier says it is working to confirm these indications.
Although the aircraft type is unconfirmed, LAM's timetable indicates that TM470 uses an Embraer 190.
All Mozambican carriers, including LAM, are blacklisted under a blanket European Commission ban.