A Gabonese airliner has crashed killing 16 people and leaving three more missing off the Gulf of Guinea coast.
The Gabon Express HS 748 is said to have nosedived into the water shortly after takeoff from Libreville on Tuesday with 30 people on board.
Meanwhile, two Britons were believed to be among five people killed when a helicopter crashed into the sea off the French Riviera, said the British embassy in Paris.
The two were aboard the Heliair Monaco helicopter when it went down 1.6 kilometres off the coast of Saint Jean Cap Ferrat in southern France.
All four passengers and the pilot died in the crash, which occurred as the single-engine Ecureuil helicopter was on its way from Nice to Monaco.
A spokesman for the principality of Monaco said the cause of the accident was unknown, adding that the weather had been good.
The Gabon plane was bound for Franceville in the southeast of the central African country when it crashed.
Eleven survivors - eight passengers and three of the four crew members - were hospitalized in Libreville, the capital of Gabon.
The office of Gabon's president announced the death toll after the emergency services had worked most of Tuesday to rescue those trapped inside the plane.
Seven French nationals were aboard the plane - five passengers and two crew members - and five of them were among the survivors, said the French embassy.
A hospital official said the survivors were in stable condition, adding they "were not seriously injured".
The plane plunged into the sea about 100 metres off the beach, close to Libreville's Leon Mba international airport, leaving only its tailplane jutting above the surface of the water.
Some hours later the wreck was fully submerged with people presumed trapped inside.
Witnesses said they saw the plane begin to head back to the airport before it suddenly crashed into the sea.
"The plane took off, then turned back with only one propeller turning," said a man who had just seen off a relative at the airport.