Vietnam is scaling back its air and sea search for missing flight MH370 as China said it will step up its search and rescue efforts to include land areas.
While Vietnam's deputy transport minister said it was suspending search and rescue operations, China said it will add two planes to its search for the missing passenger jet and its 239 passengers and crew.
The focus of the search has moved several hundred miles west of the course it should have been following.
Four days after flight MH370 vanished without trace, Malaysia Airlines said authorities were looking at evidence the Beijing-bound plane made a U-turn - a theory that was suspected early in the investigation.
The plane was last detected by civilian authorities off Malaysia's east coast, but military data reportedly suggested the jet was on the other side of the country.
But there was confusion after Malaysia's air force chief Rodzali Daud denied saying that the military last tracked the plane in that area, over the Strait of Malacca.
It comes as Malaysia Airlines investigates a report that the co-pilot on the missing flight had invited two women to stay in the cockpit for the duration of a trip two years ago .
Jonti Roos has told Australia's Channel Nine that Fariq Abdul Hamid and the other pilot talked to her and her friend, smoked and posed for photos during the flight. The second pilot was not identified.
:: Sky News will be showing a 12-minute special report on the story so far of the missing flight MH370 at 2.30pm.
Meanwhile, CIA director John Brennan has said there had been "some claims of responsibility" over the missing jet that had "not been confirmed or corroborated," and that he could not exclude the possibility of a terror link.
"We are looking at it very carefully. Clearly this is still a mystery," he said.
There were a host of unanswered questions including why the plane's transponder stopped emitting signals and what was the role of passengers carrying stolen passports, Mr Brennan said.
But officials say the two men who boarded the flight using stolen European passports appear to have been young Iranian migrants seeking a new life overseas.
Interpol confirmed the identities of the two men, and based on growing information, Interpol Secretary General Ronald Noble said he was "inclined to conclude" the plane's disappearance was not the result of a terror attack.
One of the men, Pouria Nourmohammadi, 18, who was travelling on a stolen Austrian passport, was thought to be an asylum seeker trying to reach Germany.
The other man named as Seyed Mohammed Reza Delavar, 29, was using an Italian passport.
Iran offered its assistance with the Malaysian investigation into two of its nationals.
Police also said they were investigating whether any passengers or crew had "personal or psychological problems" as a possible cause of the aircraft's disappearance, along with hijacking, sabotage, or mechanical failure.
Investigators are baffled by the lack of any wreckage and cannot understand why the black box flight recorders are not transmitting a signal. They are designed to transmit signals on contact with water.
Paul Charles, who has acted as an adviser to Malaysia Airlines, told Sky News: "It does seem likely that the aircraft disintegrated in some way at 35,000 feet. But what's most baffling about this is that the aircraft itself did not any signals.
"That's why there is no information about where this aircraft has vanished to."
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