One of them was trying to emigrate to Germany and authorities were in contact with his mother, who had been expecting her son to arrive in Frankfurt.
Richard K Noble, the international police organisation's secretary-general, said the two flew from Doha to Kuala Lumpur with Iranian passports and then switched to the stolen Austrian and Italian passports to board the Boeing 777-200 plane to Beijing.
The use of the stolen passports by two passengers on the plane raised fears that its disappearance could be linked to terrorism.