An Air France jet missing with 228 people on board ran into a towering wall of thunderstorms over the Atlantic Ocean, officials said tonight.
The area where the plane - en route from Rio de Janeiro to Paris - could have gone down was vast, in the middle of deep Atlantic Ocean waters between Brazil and the coast of Africa.
Brazil's military searched for it off its north-east coast, while the French military scoured the ocean near the Cape Verde Islands off the West African coast.
French President Nicolas Sarkozy told families of those aboard that "prospects of finding survivors were very small".
If all 228 were killed, it would be the deadliest commercial airline disaster since 2001.
Mr Sarkozy, speaking at Paris' Charles de Gaulle airport, said the reason for the disappearance remained unclear and that "no hypothesis" was excluded.
"(I met with) a mother who lost her son, a fiancee who lost her future husband. I told them the truth," he said.
Sarkozy said "it will be very difficult" to find the plane because the zone where it is believed to have disappeared "is immense".
He said France has asked for help from US satellites to locate the plane.
Chief Air France spokesman Francois Brousse said "it is possible" the plane was hit by lightning, but aviation experts expressed doubt that a bolt of lightning was enough to bring the plane down.
Air France's manager in Rio de Janeiro, Jorge Assuncao, said the two biggest groups of nationalities aboard were Brazilian and French. Other passengers were American, Angolan, Argentine, Belgian, British, Chinese, Filipino, German, Irish, Italian, Moroccan, Norwegian, Spanish and Slovakian.
Air France Flight 447, a four-year-old Airbus A330, left Rio on last night at 7.03pm local time with 216 passengers and 12 crew members on board, said company spokeswoman Brigitte Barrand.
The plane left Brazil radar contact, beyond the Fernando de Noronha archipelago, at 10.48 local time, indicating it was flying normally at 35,000ft and travelling at 522 mph.
About a half an hour later, the plane "crossed through a thunderous zone with strong turbulence". It sent an automatic message 14 minutes later at 0214 GMT reporting electrical failure and a loss of cabin pressure.
Air France told Brazilian authorities the last information they heard was that automated message reporting a technical problem before the plane reached a monitoring station near the Cape Verde islands.
Brazilian Air Force spokesman Col Jorge Amaral said seven aircraft had been deployed to search the area far off the north-eastern Brazilian coast.
"We want to try to reach the last point where the aircraft made contact, which is about 745 miles north-east of Natal," Amaral told Globo TV.
Meteorologists said tropical storms are much more violent than thunderstorms in the US and elsewhere.
"Tropical thunderstorms ... can tower up to 50,000ft. At the altitude it was flying, it's possible that the Air France plane flew directly into the most charged part of the storm - the top," Henry Margusity, senior meteorologist for AccuWeather.com, said in a statement.
Brazil's Navy said it was sending three ships to search waters about 680 miles from Natal.
Portuguese air control authorities said the missing plane did not make contact with controllers in Portugal's mid-Atlantic Azores Islands nor, as far as they know, with other Atlantic air traffic controllers in Cape Verde, Casablanca, or the Canary islands.
Air France said it expressed "its sincere condolences to the families and loved ones of the passengers and crew members" aboard Flight 447.
Air France-KLM CEO Pierre-Henri Gourgeon, at a news conference, said the plane's pilot had 11,000 hours of flying experience, including 1,700 hours flying this aircraft.
Nationalities of missing passengers
The nationalities of the 216 passengers on missing Air France Flight 447 from Rio de Janeiro to Paris, according to Air France are:
- 61 French
- 58 Brazilians
- 26 Germans
- 9 Chinese
- 9 Italians
- 6 Swiss
- 5 British
- 5 Lebanese
- 4 Hungarians
- 3 Irish
- 3 Norwegians
- 3 Slovaks
- 2 Americans
- 2 Moroccans
- 2 Spanish
- 2 Polish
- 1 Argentine
- 1 Austrian
- 1 Belgian
- 1 Canadian
- 1 Croat
- 1 Danish
- 1 Dutch
- 1 Estonian
- 1 Filipino
- 1 Gambian
- 1 Icelander
- 1 Romanian
- 1 Russian
- 1 South African
- 1 Swede
- 1 Turk