PARIS: The search continued through the night for an Air France plane that disappeared over the Atlantic, but little hope remained that any of 228 people on board would be found alive.

Air France flight AF 447 disappeared early Monday four hours into its 11-hour flight from Rio de Janeiro to Paris after the Airbus A330 encountered severe turbulence over the Atlantic and reported technical failures.

A daytime search by eight Brazilian air force aircraft doing visual sweeps did not turn up anything in the area being searched: a zone 1,100 kilometers (680 miles) off its northeastern coast.

The search was being continued overnight with a Hercules C130 fitted with equipment to try to detect the plane's emergency beacon, with another aircraft with onboard radar, and if weather conditions permit, infrared gear that could detect bodies in the water.

Officials said there was little hope of survivors from what appears to be the worst air accident in over a decade.

"The prospects of finding any survivors are very slim," a grim-faced French President Nicolas Sarkozy said after talking to stunned relatives of missing passengers. "It's a catastrophe the likes of which Air France has never seen."

Although the exact cause of the crash remained a mystery, Air France's chief executive said the aircraft had sent a series of error messages shortly after crossing an area of major turbulence.

"A succession of a dozen technical messages" sent by the aircraft around 0215 GMT showed that "several electrical systems had broken down" which caused a "totally unprecedented situation in the plane," said Pierre-Henry Gourgeon.

"It is probable that it was shortly after these messages that the impact in the Atlantic came," he told reporters at Charles de Gaulle airport, where the flight was meant to have landed on Monday morning.

Airline officials had earlier said the plane was probably hit by lightning, but Gourgeon declined to make a direct link between weather conditions and the error messages.

Brazilian President Luiz Inacio Lula da Silva said he held out hope for survivors, but added that earlier he had spoken with French President Nicolas Sarkozy by telephone "and really it was an exchange of condolences."

If it is confirmed that all 228 people on Flight AF 447 are dead, it would mark the worst loss of life in Air France's history and civil aviation's worst accident for more than a decade.

Spanish and French air forces sent out search planes to scour a vast area of ocean between Brazil and Africa. The United States also sent a surveillance aircraft and an Air Force search and rescue team in response to a request for assistance from Paris.

At Charles de Gaulle airport, tearful relatives were ushered into a private area to await developments and get counselling from a team of psychologists.

At Rio's Tom Jobim International Airport stunned relatives were shown into a closed lounge, away from the news media and into the care of psychologists and doctors.

One woman, Vasti Ester van Sluijs, told AFP she had jumped into a taxi as soon as she heard the overnight Air France flight had disappeared.

"My daughter Adriana Francesca was on the plane," she said.

Air France said the 216 passengers included 126 men, 82 women, seven children and a baby. There were 12 French crew members.

The passengers hailed from 32 countries, including 61 from France, 58 from Brazil and 26 from Germany.

French Environment Minister Jean-Louis Borloo, whose portfolio includes transport, said hijacking had been ruled out.

Airbus said the A330 has a good safety record, with no fatalities ever on a commercial flight. One did crash in 1994 during a test flight in southern France, however, killing seven people on board.

Last week Air France announced its first net loss since it merged with Dutch airline KLM in 2003 to create Europe's biggest airline.

In July 2000 all 109 passengers and crew plus four people on the ground were killed when a supersonic Air France Concorde crashed during takeoff from Charles de Gaulle airport. All Concordes were eventually taken out of service.

On August 3, 2005, an Air France A340 with 309 on board skidded off the runway after landing in a thunderstorm at Toronto's Pearson International Airport. Fourteen people suffered minor injuries.