Algerian passenger plane declares a mid-air emergency over the sea, disappears from radar as it tries to return to Algiers

An Air Algerie passenger jet travelling to Marseilles declared an emergency mid-air.

The Boeing 737-600 left Algiers this afternoon on a flight to Marseilles when it let out an emergency call. Flight radar showed the plane turn around and head back towards the point where it took-off but however the plane has now vanished off the radar.

The aircraft (similar to the plane pictured above) has about 123 seats – although it is not yet known how many passengers are on the plane.

More updates later