Kuala Lumpur, March 15 (IANS): Investigators have concluded that the missing Malaysia Airlines flight MH370 was hijacked, an official said Saturday.

According to the report cited by Xinhua, which is yet to be corroborated, the hijackers had rich flying experience and they switched off communication devices deliberately and steered the Boeing 777 aircraft off course.

Although piracy is no longer a theory, the motives are yet to be established, the official was quoted as saying.

Malaysian Prime Minister Najib Razak is scheduled to hold a press conference in Kuala Lumpur Saturday.

The Malaysia Airlines flight with 239 passengers and crew on board vanished mysteriously about an hour after taking off from Kuala Lumpur early morning March 8. It was presumed to have crashed off the Vietnamese coast in the South China Sea.

The 227 passengers on the flight included five Indians, 154 Chinese and 38 Malaysians.

Contact with the plane was lost along with its radar signal when it was flying over the air traffic control area of Ho Chi Minh City in Vietnam.

A multinational intensive search has so far failed to locate the plane.

On Friday, Malaysia confirmed that search areas for the missing aircraft had been widened to cover the Indian Ocean, but made no comment on US reports that the aircraft sent signals to a satellite for four hours after it went missing.

As of Friday, 57 ships and 48 aircraft were involved in the multinational search operation.