Interpol says two Iranians who were traveling with stolen passports were aboard the Malaysian Airlines passenger jet that remains missing.
The international police agency identified the Iranians as Pouri Nourmohammadi, 19, and Delavar Seyedmohammaderza, 29.
Interpol also released an image showing the men boarding the plane.
Interpol Secretary-General Ronald Noble said the men traveled to Malaysia on their Iranian passports then started using Austrian and Italian passports that had been reported stolen.
Noble offered his opinion that the evidence so far suggests the case of the missing plane is "not a terrorist incident."
Reuters quoted an unnamed senior military officer who had been briefed on the case as saying Malaysia's military believed the plane turned, dropped to a lower altitude, and flew some 500 kilometers to the west after it last made contact with air-traffic control.
The Boeing 777 disappeared from radar tracking on March 8 during a flight from Malaysia to Beijing with 239 people aboard.
Its whereabouts remain unknown.
Nearly 100 vessels and aircraft from 10 countries in Asia and the Pacific have joined the search in the South China Sea.
Authorities doubled the search area on March 10.
China, which had 153 of its nationals on board the plane, said it would use 10 satellites equipped with high-resolution imaging to help.
Based on reporting by AP, Reuters, AFP, CNN, and dpa