Malaysia’s acting transport minister Hishammuddin Hussein has confirmed the search had been expanded into the Indian Ocean – on the opposite side of Malaysia from where contact with the jet was lost nearly a week ago.
He also said there was evidence of a plane turning back, but it may not have been the missing flight.
It comes as sources familiar with the investigation told Reuters the plane was flown hundreds of miles off course towards the Andaman and Nicobar Islands, a chain of isles in the Andaman Sea, which is part of Indian Ocean.
“What we can say is we are looking at sabotage, with hijack still on the cards,” a Malaysian police source told Reuters.
After scouring the seas around the Andaman Islands, India has also started searching hundreds of small, uninhabited islands in the region.
Only 37 of the 572 islands in the atoll are inhabited. Most are Indian territory, but a small number in the north belong to Burma.
It comes as Chinese researchers reportedly detected an “earthquake wave” in the ocean between Malaysia and Vietnam around an hour-and-a -half after the plane last made contact.
“The seafloor event could have been caused by the plane possibly plunging into the sea,” the scientists told China’s state news agency Xinhua.
In his news conference, Mr Hishammuddin refused to address media reports, citing unidentified US officials, that the plane, which was carrying 239 people, had flown for hours after vanishing from civilian radar.
The US reports were based on information that the plane’s communication system continued to “ping” a satellite for up to four hours after it disappeared.