Malaysian Prime Minister Najib Razak said Saturday the search for a missing Malaysia Airlines passenger jet would be reoriented to the west, telling a news conference that the plane was steered off course after someone on board deliberately disabled its transponder.

Speaking in Sepang, the head of government said the plane, which went missing a week ago, altered its course toward the west and flew for five hours after its communications systems were cut.

"Up until the point at which it left military primary radar coverage, these movements are consistent with deliberate action by someone on the plane," Najib said.

Malaysian military radar lost track of the plane's signal over the Strait of Malacca, a stretch of water between the Malay Peninsula and the Indonesian island of Sumatra.

Malaysian authorities are unaware of the Boeing 777-200's whereabouts, but they believe it followed one of two possible routes and is either in a corridor extending from western Indonesia to the southern Indian Ocean or in another that stretches from northern Thailand to the border between Kazakhstan and Turkmenistan.

Flight MH370 left Kuala Lumpur on March 8 at 12:41 a.m. and was scheduled to land in Beijing roughly six hours later, but it disappeared from radar screens some 40 minutes after takeoff.

No wreckage of the plane has been found in a 14-country search that until now has focused on the South China Sea.

The aircraft - carrying 227 passengers, most of them Chinese, and a crew of 12 Malaysians - had enough fuel to fly for seven and a half hours.

The plane appeared to depart from its northerly route toward Beijing and make a sharp turn to the west after disappearing from Malaysian civilian radar, the New York Times reported, citing a "preliminary assessment by a person familiar with the data."

Soon after it climbed to 45,000 feet, above the maximum limit for a Boeing 777-200, before descending unevenly and changing its course once again from southwest-bound to a northwestern path over the Strait of Malacca and toward the Indian Ocean, the U.S. daily said.

The Malaysian prime minister did not contradict that information in his televised news conference.

"Clearly the search for (Flight) MH370 has entered a new phase," Najib said.

He refused to use the term hijacking, but his report on the missing plane points to that conclusion.

After the press conference, several police searched the home of the plane's pilot, a 53-year-old Malaysian man with 18,365 flight hours under his belt.

Najib's update was well received by the families of passengers on board the flight.

"I am thankful for the prime minister's announcement; it is clear that the plane can be traced. And this shows the plane is in a good condition and I hope that the passengers are safe," Malaysian Selamat Omar, whose 28-year-old son was on board the flight, was quoted as saying by The Malay Mail.

Eric Chen Zhi Yang, whose mother and father were traveling on the aircraft, said Najib's statement was "good news."

"It means there's still a chance my parents are alive," Yang told Malaysia's New Strait Times. EFE