Prime Minister Najib Razak said that although the movements were consistent with deliberate acts, he did not confirm that the plane was hijacked. The search operation has now expanded into new areas.

“The search for NH 370 has entered a new phase,” Prime Minister Najib Razak said today.

No questions were allowed at the press conference. Questions will be allowed at a follow-up conference at 5:30 p.m. local time, officials said.

The flight was carrying 239 people when it went missing over waters between Malaysia and Vietnam. A frantic search followed, with 14 different countries involved.

Information revealed Friday suggested that the missing jetliner made a turn up the Strait of Malacca around the time air traffic controllers lost contact with the plane, a senior U.S. official who has been briefed on the investigation told ABC News.

The turns are indicative of someone at the controls of the plane, the official suggested – an assessment that other experts seemed to agree with. "That indicates that somebody may be on the controls," said Tom Haueter, a former director of the National Transportation Safety Board's Office of Aviation safety. "Slight turns I can see, but if somebody is making a major heading change, that would appear to be an intentional input to the controls." Added Stephan Ganyard, an ABC News aviation consultant, "We are seeing what we call heading changes, where the aircraft changes its nose position and moves around the sky. This would confirm that we are seeing an airplane that's being controlled by pilots or somebody in that aircraft."

The Boeing 777’s communication with the ground was severed under one hour into the March 8 flight from Kuala Lumpur to Beijing. The plane’s communication systems were shut down separately, two U.S. officials said., an indication that the plane did not come out of the sky because of a catastrophic failure.

The data reporting system, they believe, was shut down at 1:07 a.m. The transponder – which transmits location and altitude – shut down at 1:21 a.m. The missing flight continued to “ping” a satellite on an hourly basis after it lost contact with radar, senior administration officials told ABC News.

Authorities have spent the past week investigating – and later dismissing – leads. Two oil slicks were determined to not be from the plane and an orange object thought to be part of the plane’s door was investigated and found to be unrelated.