KUALA LUMPUR - Malaysian Prime Minister Najib Razak on Saturday denied reports that a missing Malaysian flight bound for Beijing had crashed.

"The search and rescue operations will continue as long as necessary," Najib told reporters in Kuala Lumpur.

He said the search area has been enlarged after rescuers failed to locate the missing plane from its last point of contact.

Multinational rescue efforts have been launched to try and locate the Malaysian Airlines Boeing 777-200 passenger plane after it lost contact en route from Kuala Lumpur to Beijing early Saturday.

There were 239 people onboard, including more than 150 Chinese.

Malaysian Transport Minister Hishamuddin Hussein had said earlier that no sign of any plane wreckage had been found, denying media reports that the plane had crashed south of an island off Vietnam.

Asked whether the incident is a terrorist attack, Najib said: "We are looking at all possibilities but it is too soon to speculate."