The head of Interpol said on Tuesday that he does not believe the missing Malaysian plane was part of a terrorist plan, the Irish Times reported.

"The more information we get, the more we are inclined to conclude it is not a terrorist incident," said Interpol Secretary General Ronald Noble. 

Noble added that two people aboard the flight, who had their own passports, switched them with stolen Italian and Austrian passports in Kuala Lumpur. 

Additionally, authorities in Malaysia said one of the two men who boarded with a stolen passport was an Iranian with no connection to terrorist organizations. 

Pouria Nour Mohammad Mehrdad, 19, used the stolen Austrian passport to end up in Germany, according to Inspector General of Police Khalid Abu Bakar.

Khalid said Mehrdad received a proper visa when he entered Malaysia.

"We have been checking his background, we have also checked him, with other police organizations, on his profile, and we believe that he is not likely to be a member of any terrorist group," he added. 

Authorities are currently investigating whether the missing MH 370 was hijacked, bombed, or suffered from a mechanical failure. However, with a lack of any evidence and no indication of problems during the flight, officials are left with very little to analyze.

"Maybe somebody on the flight has bought a huge sum of insurance, who wants family to gain from it or somebody who has owed somebody so much money, you know, we are looking at all possibilities," Bakar said.

"We are looking very closely at the video footage taken at the KLIA (Kuala Lumpur International Airport), we are studying the behavioral pattern of all the passengers."

After vanishing on early Saturday, naval ships and aircrafts from at least 10 different nations have began searching for any sign of the plane.

"Until now, with all of our efforts, there is very little hope for any good news about this plane," said Pham Quy Tieu, head of Vietnam's search and rescue effort.