Prime Minister Najib Razak said the investigation has shifted to focus on passengers and crew members after data showed the plane deviated from its course due to the deliberate action of someone on board the plane, CNN reported.
"Malaysian authorities have refocused their investigation on crew and passengers aboard," Najib told reporters Saturday. "Evidence is consistent with someone acting deliberately from inside the plane."
"Despite media reports that the plane was hijacked, we are investigating all major possibilities on what caused MH370 to deviate," he said.
Flight 370 disappeared on March 8 as it flew from Kuala Lumpur to Beijing with 239 people, mostly Chinese, aboard.
"Based on new satellite information, we can say with a high degree of certainty that the aircraft communications ... system was disabled just before the aircraft reached the East Coast of peninsular Malaysia," Najib said. "Shortly afterward, near the border between Malaysian and Vietnamese air traffic control, the aircraft's transponder was switched off."
The BBC reported that investigators are working to obtain radar data from any of the countries the plane may have passed over when it when off course. Those countries could include Thailand, Myanmar, Nepal, Bangladesh, Bhutan, China, India and Pakistan.
Najib said investigators are looking into all possibilities as to what caused Flight 370 to disappear, Malaysia's Bernama news agency reported.
"Over the last seven days, we have followed every lead and looked into every possibility. For the families and friends of those involved, we hope this new information brings us one step closer to finding the plane," he said in a media briefing.