"CNN has learned that a classified analysis of electronic and satellite data suggests the flight likely crashed either in the Bay of Bengal or elsewhere in the Indian Ocean," the leading American channel reported while noting that the Malaysian Prime Minister Najib Razak said some of those areas have been searched.
Ahead of Najib's announcement, US officials told the channel that flight MH370 made drastic changes in altitude and direction after disappearing from civilian radar.
The changes raised questions on who was at the controls of the Boeing 777-200 ER jetliner when it vanished along with 239 people, including five Indians, who were flying from Kuala Lumpur to Beijing on March 8.
The more the United States learns about the flight's pattern, "the more difficult to write off" the idea that some type of human intervention was involved, an official familiar with the investigation was quoted as saying by CNN.
"Malaysian authorities have refocused their investigation on crew and passengers aboard," Najib told reporters today, a week after the plane vanished mysteriously from radar screens
"Evidence is consistent with someone acting deliberately from inside the plane," Najib said, stopping short of calling it a hijacking, saying investigators have not made a final determination.
Taken together, the data point toward speculation of a dark scenario in which someone took control of the plane for some unknown purpose, perhaps terrorism, CNN quoted American investigators as saying.
The jetliner was flying "a strange path," a US official said on condition of anonymity.
Malaysian military radar showed the plane climbing to 45,000 feet soon after disappearing from civilian radar screens and then dropping to 23,000 feet before climbing again, the official said.
Earlier, the New York Times reported that Flight 370 experienced significant changes in altitude after it lost contact with ground control, and altered its course more than
once as if still under the command of a pilot.
Radar signals recorded by the Malaysian military appeared to show that the missing airliner climbed to 45,000 feet, above the approved altitude limit for a Boeing 777-200, soon after it disappeared from civilian radar and turned sharply to the west, the Times quoted a preliminary assessment by a person familiar with the flight data.
The radar track, which the Malaysian government has not released but says it has provided to the United States and China, showed that the plane then descended unevenly to 23,000 feet, below normal cruising levels, as it approached the
densely populated island of Penang, it said.
There, officials believe, the plane turned from a Southwest-bound course, climbed to a higher altitude and flew northwest over the Strait of Malacca toward the Indian Ocean.
Investigators have also examined data transmitted from the plane's Rolls-Royce engines that showed it descended 40,000 feet in the span of a minute, according to a senior American official briefed on the investigation.