RIO DE JANEIRO, July 2 (RIA Novosti) - The exact cause of the June 1 Air France plane crash that took the lives of all 228 people on board has not been determined, the airline's CEO has said.

France is to publish the first official report into the crash later in the day.

Air France Flight 447 from Rio de Janeiro to Paris lost contact with ground controllers on June 1 about three hours into the flight. The accident was the worst in the airline's 75-year history, and the world's worst for almost a decade.

"[The report] does not answer the question as to exactly what happened, or the sequence of events that led to the accident," Air France CEO Pierre-Henri Gourgeon said at a meeting with the relatives of the Airbus A300 crash on Wednesday.

Aviation experts expect the report to announce the results of the examination of the wreckage and forensic findings.

Over 600 pieces of the plane and 51 bodies have been discovered. The black boxes were not recovered. Brazil called off the search on June 27.