The fate of the Boeing 777-200 with 239 people onboard has confounded the six-nation international search and rescue mission scouring the area by sea and air since it disappeared at 1.30am yesterday.
Malaysia's Department of Civil Aviation (DCA) is expected to announce the latest updates at a press conference scheduled for 9am today.
Malaysia's air force and maritime agencies will resume air search operations this morning for the aircraft, which has one of the best safety records in the world.
The 11-year-old Boeing, powered by Rolls-Royce Trent engines, took off at 12.40am from Kuala Lumpur International Airport for Beijing and was apparently flying in good weather conditions when it disappeared without a distress call.
Flight MH370 last had contact with air traffic controllers 120 nautical miles off Kota Baru.
Flight tracking website flightaware.com showed it flew northeast after takeoff, climbed to 10,700m and was still climbing when it vanished from tracking records.
A crash, if confirmed, would likely mark the 777's second fatal incident in less than a year, and its deadliest since entering service 19 years ago. An Asiana Airlines Boeing 777-200ER crash-landed in San Francisco in July 2013, killing three passengers and injuring more than 180.
Boeing said it was monitoring the situation but had no further comment.
A large number of planes and ships from several countries were scouring the area where the plane last made contact, about halfway between Malaysia and the southern tip of Vietnam.
"The search and rescue operations will continue as long as necessary," Prime Minister Datuk Seri Najib Razak told reporters, adding that Malaysia had deployed 15 air force aircraft, six navy ships and three coast guard vessels.
Vietnam said its rescue planes had spotted two large oil slicks, about 15km long, and a column of smoke off its coastline, but it was not clear if they were connected to the missing plane.
China and the Philippines also sent ships to the region to help, while the United States, the Philippines and Singapore dispatched military planes. China also put other ships and aircraft on standby.
Bernama reports that the Department of Civil Aviation will extend the search and rescue operation to the Straits of Malacca.
The director-general of civil aviation Datuk Azharuddin Abdul Rahman said it had concentrated its efforts on the South China Sea but would now extend its search to the west coast of the peninsula. – March 9, 2014.