One of the two men travelling on a missing Malaysian Airlines jetliner with stolen passports was a 19-year-old Iranian believed to be seeking asylum in Germany, officials said Tuesday.
Baffled authorities have expanded their search for the Boeing 777 on the opposite side of the country from where it disappeared nearly four days ago with 239 people on board.
In the absence of any sign that the plane was in trouble before it vanished, speculation has ranged widely, including pilot error, plane malfunction, hijacking and terrorism, the last because two passengers were traveling on stolen passports.
The terrorism theory weakened after Malaysian authorities determined that one of the two men was an Iranian asylum seeker.
Malaysian police chief Khalid Tan Sri told reporters the 19-year-old Iranian man was believed to be planning to enter Germany to seek asylum.
He said the man was not believed to be a member of a terrorist group. He said the young man's mother was waiting for him in Frankfurt and had been in contact with the police.
He said she contacted Malaysian authorities to inform them of her concern when her son didn't get in touch with her.
Khalid said the other man travelling with the Iranian had arrived in Malaysia on the same day, and had yet to be identified.
He said investigators had not ruled out any possibility, including hijacking, sabotage or a personal motive to down the plane by either the crew or passengers.
He also said that the police ''had no prior information or intelligence about any involvement of terrorists.''
The plane took off from Kuala Lumpur, on the western coast of Malaysia, early Saturday en route to Beijing.
It flew overland across Malaysia and crossed the eastern coast into the Gulf of Thailand at 35,000 feet (11,000 metres).
There it disappeared from radar screens. The airline says the pilots didn't send any distress signals, suggesting a sudden and possibly catastrophic incident.
In a statement, Malaysia Airlines said search and rescue teams ''have expanded the scope beyond the flight path to the West Peninsula of Malaysia at the Straits of Malacca.''
An earlier statement had said the western coast of Malaysia was ''now the focus,'' but the airline subsequently said that phrase was an oversight.
''The search is on both sides,'' Civil aviation chief Azharuddin Abdul Rahman said, adding that the previous statement didn't mean that the plane was more like to be off the western coast.
The new statement said authorities are looking at a possibility that MH370 attempted to turn back toward Kuala Lumpur.
If it did indeed retrace its path, the plane could conceivably have crashed into the sea on the western coast, the other side of Malaysia from where it was reported missing.
But this doesn't explain why it did not continue to show on radar while flying back toward Kuala Lumpur, and Malaysia Airlines or other authorities have not addressed that question.
''All angles are being looked at. We are not ruling out any possibilities,'' is all that the Malaysia Airlines statement said.
Malaysia's air force chief also said Sunday there were indications on military radar that the jet may have done a U-turn.
Over the last three days the search mission has grown to include nine aircraft and 24 ships from nine countries, which have been scouring the Gulf of Thailand on the eastern side of Malaysia.
Apart from the sea, land areas are also being searched.
China, where two-thirds of the passengers were from, has urged Malaysian authorities to ''speed up the efforts'' while also contributing ships and helicopters to the search.
A shopping mall in Beijing suspended advertising on its large outdoor LED screen to display a search timer - an image of an airplane along with a digital clock marking the time since contact with the flight was lost.
Authorities questioned travel agents Monday at a beach resort in Thailand who police say were involved in handling reservations and issuing tickets used by the Iranian asylum seeker and his companion.
Both men had both booked onward flights to Europe, and were travelling on stolen passports of an Italian and an Austrian. The identity of the other man is not known yet.
Assuming the plane crashed into the ocean or disintegrated in midair, there will likely still be debris floating on the ocean, but it may be widely spaced out and the bulk of it may have already sunk.
The United States has sent two navy ships, at least one of which is equipped with helicopters, and a Navy P-3C Orion plane that onboard sensors allow the crew to clearly detect small debris in the water.
It said in a statement that the Malaysian government had done ''tremendous job'' organising the land and sea effort.
The hunt began on Saturday morning at the point the plane was last known to be. But with no debris found, the search has been systematically expanded to include areas where the plane could have in theory ended up given the amount of fuel it had on board.
That is an area many thousands of square kilometres wide. Vietnamese planes and ships are a major component of the international search and rescue effort.
Lt. Gen. Vo Van Tuan, deputy chief of staff of Vietnamese People's Army, said authorities on land had also been ordered to search for the plane, which could have crashed into mountains or uninhabited jungle.
He said that military units near the border with Laos and Cambodia had been instructed to search their regions also.
''So far we have found no signs (of the plane) ... so we must widen our search on land,'' he said.