Egypt has sent a robot submarine to join the hunt for an EgyptAir plane that crashed in some of the deepest waters of the Mediterranean Sea with 66 people on board, President Abdel Fattah al-Sisi said on Sunday.

Ships and planes scouring the sea north of the city of Alexandria have found body parts, personal belongings and debris from the Airbus 320, but are still trying to locate the black box recorders that could shed light on the cause of Thursday's crash.