An Egyptian charter plane has crashed into the Red Sea, killing all 148 passengers and crew on board.
Deep water at the crash site is making recovery work difficult
The plane went down shortly after leaving the resort of Sharm el-Sheikh.
Most of the passengers were French tourists, including many children, returning from holiday to Charles de Gaulle airport in Paris.
French and Egyptian officials have said preliminary findings suggest the crash was caused by technical failure, developed minutes after take-off.
The emergency services were alerted when the plane, a Boeing 737 belonging to Egyptian charter company Flash Airlines, disappeared from radar screens shortly after take-off at 0244 GMT.
There was no distress call from the plane to the control tower.
Egyptian search and rescue teams - in boats, planes and helicopters - have found wreckage in the sea off the Naama Bay area of Sharm el-Sheikh.
Police speedboats have been fishing luggage and small pieces of wreckage from the water, and at least one body has been recovered.
Local divers say the plane came down in very deep water, perhaps too deep to recover either the majority of the dead or the black box flight recorder, reports the BBC's Paul Wood in Cairo.
There were 135 passengers and 13 crew members on the flight, which was on its way to Cairo for a stopover and crew change before heading on to Paris.
In Paris, the authorities at Charles de Gaulle airport have taken relatives of the victims to a nearby hotel for counselling and medical treatment for shock.
Most had already heard about the crash on the news, but a handful still turned up still expecting to greet family members returning from their holidays.
According to one of the counsellors helping relatives, many of those on board the flight were children and included one family of seven.
President Jacques Chirac has telephoned his Egyptian counterpart, Hosni Mubarak, "to get a total picture on the circumstances of the tragedy," his office said.
France has offered to send a team of experts to help with the recovery operation and the investigation.
In Paris, the justice minister asked prosecutors to open a preliminary manslaughter inquiry - a move that does not prejudge the causes but provides a legal framework for French officials to carry out an investigation.
The aircraft had brought a group of Italian passengers to Sharm el-Sheikh and took off an hour later with the French holiday-makers on board.
The crash comes amid increased alerts about possible terrorist threats that have led to tightened security and cancelled flights around the world.
"The plane had a problem at take-off and then tried to turn around and it was at that moment that it apparently crashed off the coast," French Deputy Transport Minister Dominique Bussereau told reporters at Charles de Gaulle airport.
Private Egyptian charter airline
Operates two Boeing 737-300s - both manufactured in 1993
Planes equipped with the latest navigational instruments, company says
Pilots have minimum of 5,000 hours flying time, company says
Egyptian authorities also moved quickly to quash any suggestion that this was a terrorist attack.
Aviation Minister Ahmed Shafiq said the cause of the crash appeared to be entirely technical.
A terrorist attack on Egyptian soil would be devastating to the country's tourist industry, says our correspondent.
Tourism is Egypt's main foreign currency earner, producing about $4bn a year and accounting for 11% of GDP.
Sharm el-Sheikh is a popular Red Sea tourist resort that also often plays host to political and economic summits.
The Flash Airlines aircraft was only 10 years old, was regularly serviced in Norway, and captained by a pilot with more than 5,000 hours of flying experience.