The French navy said Monday that one of its ships has joined the search for the wreckage of EgyptAir Flight 804, focusing especially on the hunt for its flight recorders, as questions remain over what caused the Airbus 320 to crash over the Mediterranean, killing all 66 on board, ABC News reported on Monday.

Ships and planes from Britain, Cyprus, France, Greece and the United States are taking part in the search for the debris from the aircraft, including the black boxes. Some wreckage, including human remains, has been recovered already.

The French vessel is equipped with sonar that can pick up the underwater "pings" emitted by the recorders. It is specialized in maritime surveillance, and rescue and marine police missions.

The 80-meter (262-foot) ship left its Mediterranean home port of Toulon Friday with a crew of 90, including two judicial investigators. The search area is roughly halfway between Egypt's coastal city of Alexandria and the Greek island of Crete, where water is 8,000 to 10,000 feet (2,440 to 3,050 meters) deep.

Source: MENA