by Stephane Jourdain

PARIS, June 1, 2009 (AFP) - An Air France jet carrying 228 people on a Rio de Janeiro-Paris flight went missing over the Atlantic on Monday amid mounting fears it had crashed into the ocean.

French Environment Minister Jean-Louis Borloo said the plane had probably had an accident as a hijacking had been ruled out.

Air France said it had "had no news" for several hours from Flight AF 447 and the Brazilian Air Force said it had launched a search and rescue operation in the Atlantic.

The Airbus A-330 jet was carrying 216 passengers and 12 crew and should have arrived in Paris-Charles de Gaulle Airport at 0910 GMT.

"We are very worried," a French aviation official said.

"The plane disappeared from the screens several hours ago. It could be a transponder problem, but this kind of fault is very rare and the plane did not land when expected."

Another Paris airport official said there appeared to be "no hope" that the jet would be recovered safely.

"In his last communication, the captain said there was turbulence and afterwards contact was lost," the official said, speaking on condition of anonymity.

Flight AF 447 left Rio at about 7:00pm (2200 GMT) on Sunday night. Rio and Paris lie 9,145 kilometres (5,282 miles) apart, or an approximate flight time of 10 hours 20 minutes, with almost all of the journey over the Atlantic.

The Brazilian air force said its planes had scrambled to search for the jet in waters off its eastern coast near the island of Fernando de Noronha, 2,400 km northeast of Rio, Brazilian aviation officials said.

Airport authorities have set up a crisis cell at Charles de Gaulle, and junior transport minister Dominique Bussereau was due at the scene. The French foreign ministry also activated its own crisis cell.

The airline said it "shared the emotion and the concern of the families concerned" and said friends and relatives waiting at the scene would be taken in hand by officials and cared for in a dedicated waiting area.

President Nicolas Sarkozy's office said he had been informed of the crisis and ordered all relevant government agencies to hunt "for any sign of the plane and to quickly shine a light on the reasons for its disappearance."

Five Italians were believed to be on the jet, according to Italian media.

The French foreign ministry said it had set up a crisis centre over the incident.