Malaysia defended its hunt for the missing Boeing 777 Wednesday but acknowledged it is still unsure which direction the plane was headed when it disappeared, highlighting the massive task facing the international search. But government officials said they asked India to join in the search near the Andaman Sea, suggesting they think the jetliner and the 239 people on board might have reached those waters after crossing into the Strait of Malacca, some 250 miles from the flight's last known coordinates.
Amid intensifying confusion and occasionally contradictory statements, the country's civil aviation authorities and the military said Flight MH370 may have turned back from its last known position between Malaysia and Vietnam, possibly as far as the Strait of Malacca, a busy shipping lane off Malaysia's western coast.
How the aircraft might have done this without being clearly detected by radar remains a mystery, raising questions over whether its electrical systems, including transponders allowing it to be spotted, were either knocked out or turned off. If it did manage to fly on, that would challenge earlier theories that the plane may have suffered a catastrophic incident, initially thought reasonable because it didn't send out any distress signals.
The search area has been expanded to almost 27,000 nautical square miles (an area roughly equivalent to the state of Indiana), authorities said, adding that 43 ships and 39 aircraft from eight nations have been deployed to search for MH370. Malaysian Defense Minister Hishammuddin Hussein described the multinational search as unprecedented.
"Our immediate focus is to find the aircraft," said Malaysian Acting Transport Minister Hishammuddin Hussein. "We are focusing on both the South China Sea and Straits of Malacca."
Authorities have not ruled out any possible cause, including mechanical failure, pilot error, sabotage or terrorism. Both the Boeing 777 and Malaysia Airlines have excellent safety records.
Malaysia Airlines flight MH370 took off from Kuala Lumpur for Beijing early Saturday and fell off civilian radar screens at 1:30 a.m. about 35,000 feet above the Gulf of Thailand between Malaysia and southern Vietnam. It sent no distress signals or any indication it was experiencing any problems.
Malaysian authorities said Wednesday that a review of military radar records showed plots of what might have been the plane turning back, crossing over the country and flying to the Strait of Malacca.
Air force chief Gen. Rodzali Daud said the radar showed an unidentified object at 2:15 a.m. about 200 miles northwest of Penang.
"I am not saying it's flight MH370. We are still corroborating this. It was an unidentifiable plot," he said.
Rodzali released a statement denying remarks attributed to him in local media saying that military radar had managed to track the aircraft turning back from its original course, crossing the country and making it to the Strait of Malacca.
Asked about this at a press conference, Hishammuddin said his government had been transparent from the start.
"There is only confusion if you want to see confusion," he said. "Basically, we have been very consistent on what we've been saying the last few days."
The confusion has prompted speculation that different arms of the government have different opinions over where the plane is most likely to be, or even that authorities are holding back information.
The Strait of Malacca, which separates Malaysia from Indonesia's Sumatra Island, is some 250 miles from where Flight MH370 was last known to have made contact with ground control officials over the Gulf of Thailand early Saturday.
Indonesia Air Force Col. Umar Fathur said the country had received official information from Malaysian authorities that the plane was above the South China Sea, about 12 miles from Kota Bharu, Malaysia, when it turned back toward the strait and then disappeared. That would place its last confirmed position closer to Malaysia than has previously been publicly disclosed.
On Sunday, Malaysia Airlines said it was "fearing the worst," and the government said it was investigating four passengers who may have held false identity documents. Malaysian investigators are checking the identities of those four people but have not determined if the plane was downed by an attack, Hishammuddin said.
If all those on board are confirmed dead, it would be the deadliest commercial air accident in 10 years.
Choi Tat Sang, a 74-year-old Malaysian man, said his family is still holding out hope that the plane and all on board are safe. His daughter-in-law, Goh Sock Lay, 45, was the chief stewardess on the flight. Her 14-year-old daughter, an only child, has been crying every day since the plane's disappearance.
"We are heartbroken. We are continuing to pray for her safety and for everyone on the flight," he said. "All right, good night" were the final words heard by air traffic controllers from the missing Malaysia Airlines flight before it vanished over the South China Sea, relatives of the passengers were told Wednesday.