Malaysia's military is looking into the "possibility" that the missing Boeing 777 turned and flew hundreds of miles to the west but can't say for certain it reached the Malacca Strait, along the country's west coast, a transport official told NBC News.
The update from the Malaysian Transport Ministry comes after Reuters reported Tuesday that the plane changed course after it last made contact with civilian air traffic control Saturday, about an hour after takeoff from Kuala Lumpur heading for Beijing.
A senior military officer told Reuters that the plane "changed course after Kota Bharu and took a lower altitude. It made it into the Malacca Strait."
V. Mano, head of the transport ministry's crisis communications, denied that anyone from the military has said the plane reached the Malacca Strait, although pilots are scouring both the western and eastern coasts of Malaysia.
He also said no one in the military has claimed that the plane took a "low altitude."
If the plane did head west, that would appear to rule out sudden catastrophic mechanical failure, as it would mean the aircraft flew around 350 miles at least after its last contact with air traffic control, although its transponder and other tracking systems were off.
A non-military source familiar with the investigations told Reuters the report was one of several theories and was being checked.
At the time it lost contact with civilian air traffic control, the plane was roughly midway between Malaysia's east coast town of Kota Bharu and the southern tip of Vietnam, flying at 35,000 feet.
A huge search operation for the plane has been mostly focused on the shallow waters of the Gulf of Thailand off Malaysia's east coast, although the Strait of Malacca has been included since Sunday.