Malaysia has again expanded the vast area where it is looking for the missing jetliner with 239 people on board, but acknowledges it is likely a search mission rather than a rescue effort.
Transport Minister Hishammuddin Hussein said Wednesday that ships and aircraft from 12 countries are now searching more than 90,000 square kilometers of water, looking for a Boeing 777 aircraft that disappeared from air traffic radar screens early Saturday.
He said the fifth day of the search is focused on the Strait of Malacca and the South China Sea, but now also extends far to the northwest to waters near India's Andaman and Nicobar islands.
He rejected growing criticism from some aviation experts outside Malaysia that the search has become mired in confusion, with Malay officials issuing contradictory reports about the effort.
Hishammuddin said officials have turned over military radar information to American air safety experts to try to determine whether Flight 370 reached the Strait of Malacca, hundreds of kilometers to the west from its last known sighting on civilian radar north of Malaysia. He said officials are still not sure whether the two radar systems are both detecting the missing jet.
Hishammuddin said he fears the search and rescue mission will just become a search, but that authorities have an obligation to the families of those aboard the jet to find the missing aircraft.
"So many vessels and aircraft, so many countries to coordinate, and a vast area for us to search. And each time that passes, I fear that the search and rescue becomes just a search, but we will never give up hope. And this we owe to the families."
Hishammuddin said Malaysia is dealing with an "unprecedented" situation and will do "whatever it takes" to find the jet.
"My heart reaches out to the families of the passengers and crew, and I give you my assurance that we will not reduce the tempo and that we will not spare any effort to find the missing plane."
At a news conference, the minister said 42 ships and 39 aircraft from the 12 countries have so far "found nothing" in their search.
Earlier Wednesday, the Malaysian military backed away from statements that it last tracked the plane in the strait, which is one of the busiest shipping lanes in the world.
If the plane did make it to the Strait of Malacca, it would call into question theories that the jet experienced some sort of sudden catastrophic event shortly after takeoff that prevented pilots from communicating with authorities.
The plane disappeared from civilian radar without any distress calls about an hour after leaving Kuala Lumpur en route to Beijing early Saturday, when weather conditions appeared to be clear.
Many relatives of those on the plane are growing frustrated with a lack of answers and sometimes contradictory information from the Malaysian government.
After meeting with Malaysian government representatives Wednesday in Beijing, one family member, who identified herself as Ms. Li, said she does not feel sufficiently informed.
"I'm not very satisfied (with the meeting). There are many things that have still not been clearly explained and they still haven't met our requests."
China's government also said Wednesday that the conflicting information on the plane's course was "pretty chaotic."
Meanwhile, new allegations arose concerning past behavior of one of the plane's pilots. A South African woman, Jonti Roos, told Australia's Channel Nine TV the plane's first officer, Fariq Abdul Hamid, invited her and another woman into the cockpit on a flight two years ago.
Roos shared several pictures that appear to show her posing with Fariq and his co-pilot. She said the men talked and flirted with her for the entire flight from Thailand to Kuala Lumpur in December 2011.
In a statement, Malaysia Airlines said it was "shocked" by the allegations, which it said it takes "very seriously." The airline said it has not been able to confirm the validity of the pictures.
Malaysian officials have been exploring scenarios of what may have brought down the jet, including an explosion, hijackers, pilot error or mechanical failure.
About two-thirds of the people on board were Chinese nationals, with the remainder from other Asian countries, Europe and North America.