(TheBlaze/AP) — U.S. officials told NBC News Saturday that they are probing terror concerns after two individuals listed as passengers on a missing Malaysia Airlines flight had previously reported their passports stolen and turned out not to be on the plane.

“We are aware of the reporting on the two stolen passports,” a senior official reportedly said. “We have not determined a nexus to terrorism yet, although it’s still very early, and that’s by no means definitive.”

This photo provided by Laurent Errera taken Dec. 26, 2011, shows the Malaysia Airlines Boeing 777-200ER that disappeared from air traffic control screens Saturday, taking off from Roissy-Charles de Gaulle Airport in France. The Malaysia Airlines Boeing 777-200 carrying 239 people lost contact with air traffic control early Saturday morning, March 8, 2014 on a flight from Kuala Lumpur to Beijing, and international aviation authorities still hadn't located the jetliner several hours later. (AP Photo/Laurent Errera)

This photo provided by Laurent Errera taken Dec. 26, 2011, shows the Malaysia Airlines Boeing 777-200ER that disappeared from air traffic control screens Saturday, taking off from Roissy-Charles de Gaulle Airport in France. (AP Photo/Laurent Errera)

According to NBC News, U.S. officials are sifting through intelligence and looking into passenger manifests.

On Saturday, a Malaysia Airlines jet carrying 239 people disappeared. Authorities have since not been able to locate the plane, though the Vietnam air force spotted two oil slicks suspected to have come from the airliner.

Foreign ministry officials in Rome and Vienna confirmed Saturday that names of two nationals listed on the manifest of the missing flight match passports reported stolen in Thailand. Neither European was on the plane; the Italian was traveling in Thailand and the Austrian was located in his native country.

The father of the Italian man told The Associated Press that his son’s passport had been stolen a year and a half ago while traveling in Thailand.

“He deposited it with rental car agency, and when he returned the car it was gone,” Walter Maraldi said by telephone from his home in the northern Emilia-Romagna region.

Walter Maraldi said authorities could not tell him whether the stolen passport or a counterfeit copy was used by a passenger to board the aircraft.

The father said his son Luigi Maraldi, 37, called his parents from Thailand to tell them he was fine after hearing news reports that an Italian with his name was on board the missing airplane.

Austrian Foreign Ministry spokesman Martin Weiss confirmed that a name listed on the manifest matches an Austrian passport reported stolen two years ago in Thailand. Weiss would not confirm the Austrian traveler’s identity.

“We have no information on who might have stolen the passport,” Weiss said.

This is a developing news story. Updates will be added.

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