A Senegal-bound medical evacuation plane with seven people aboard appears to have collided with a much larger Boeing 737 shortly before disappearing from radar screens.
The private Senegalair plane was carrying a French patient as well as a doctor, two nurses and three crew members from Burkina Faso's capital Ouagadougou to Senegal's Dakar on Saturday night. But it overshot the coastal capital by more than 100 km (60 miles) and then vanished above the Atlantic Ocean.
Search and rescue efforts continued on Monday.
"According to initial information, there was a collision between two aircrafts and we are seeking to either confirm or to rule this out with the technical investigation," said the director general of Senegalese civil aviation authority ANACIM, Magueye Marame Ndao, in a statement.
At 18:13 GMT on Saturday, about an hour before vanishing, the medevac plane crossed paths with a Boeing 737-800 operated by Ceiba Airlines about 555 km from Dakar, the statement added.
The Ceiba flight, originally due to fly from Dakar to Benin's capital Cotonou, later landed in Malabo in Equatorial Guinea where the airline is based.
Among the other passengers on board the medevac plane were two Algerians and a citizen of Congo, the aviation authority previously said, without specifying if that meant Democratic Republic of Congo or Republic of Congo.