French Prime Minister Manuel Valls said that no assumption can be ruled out at this stage on the causes of the disappearance of the Airbus A320 of the EgyptAir airline. No assumption can be ruled out at this stage on the causes of the disappearance of the Airbus A320 of the Egyptian EgyptAir airline that disappeared in the night from Wednesday to Thursday en route from Paris to Cairo, French Prime Minister Manuel Valls said Thursday. "No hypothesis can be rejected at the current stage on the causes of this [aircraft's] disappearance," Valls told the RTL broadcaster. France is ready to participate in searches for the missing plane, he stressed. French Foreign Minister Jean-Marc Ayrault on Thursday said French aircraft and ships will be sent into the area of the missing EgyptAir passenger jet that disappeared in Mediterranean Sea to help with search and rescue efforts. Greece and Egypt's armed forces have both joined efforts in searching for the missing plane. Egypt Air Flight MS804 departed from the Charles de Gaulle Airport in Paris at 23:09 GMT. The aircraft was heading for Cairo International Airport. According to the airline, there were a total of 66 people on board the plane, including 56 passengers.