White House press secretary Jay Carney spoke guardedly about the reason for the disappearance of a Malaysia Airlines jet today as suspicions swirled about the stolen passports used to purchase a pair of one-way tickets on the doomed flight.

Italian Luigi Maraldi lost his passport in Phuket, Thailand, in 2013, while Austrian Christian Kozel lost his in the same resort city in 2012. Both men were listed as among the 239 on board the flight but are very much alive.

The Financial Times reported that a man believed to be Iranian and identifying himself as Ali booked the two tickets at the last minute through a Thai travel agent, who was paid in cash by an associate of Ali.

The ticket holders were supposed to transfer in Beijing with Amsterdam as the ultimate destination.

“Obviously, the Malaysians have the lead in this investigation, but we do not have enough information at this time to comment on the cause,” Carney said at today’s press briefing.

Officials from the National Transportation Safety Board and Federal Aviation Administration are en route to the region to help out, he said.

Despite a massive air and sea search in the Gulf of Thailand, authorities have not been able to locate any wreckage from the plane, which sent no distress signal before it disappeared off radar.

Three American citizens were on board, including 50-year-old Philip Wood, who was working for IBM in Malaysia, and children Nicole Meng and Leo Meng.

The Defense Department said the 7th Fleet sent the USS Pinckney, an Arleigh Burke-class guided missile destroyer, to the scene with MH-60R helicopters equipped for search efforts. A PC-3 Orion aircraft from Okinawa has also arrived in the region to contribute long-range search radar and communications capability.

“The United States government is in communication with agencies and with — across agencies, rather, and with international partners to provide any appropriate assistance in the investigation,” Carney said.

At the State Department today, spokeswoman Jen Psaki was asked whether the administration’s concern has been piqued about “any potential Iranian hand in what went on here.”

“The reports that there were two stolen passports raised concerns and questions. But I don’t have any other confirmation of what you just said from our end or any other details into the investigation. Obviously, it’s being looked into,” Psaki said.

Rep. Peter King (R-N.Y.), who sits on the Homeland Security and Intelligence committees, told CNN this afternoon that there are “all of these red flags” surrounding the disappearance of Flight MH370.

“The fact is that the plane went down without any communication whatsoever, the fact that you had the two passengers flying with stolen passports, now this report, which I don’t believe is confirmed yet by the United States, but assume that it’s true, about an Iranian purchasing the tickets,” King said. “And then an add added factor that Malaysia has had al-Qaeda activity in the past, both prior to 9/11 and prior to the USS Cole, the fact that you have Uighurs, which is a Chinese Islamic group, in that area, you add all that together, and the mystery of it, certainly, every possible terrorist lead or every possible terrorist scenario has to be drilled down and has to be looked at exhaustively.”

A group called Chinese Martyrs’ Brigade reportedly emailed a statement to Chinese journalists Monday claiming responsibility for the doomed flight, saying: “You kill one of our clan, we will kill 100 of you as pay back.” Malaysian authorities doubted the claim’s credibility.

King stressed that from what he’s learned from the intelligence community, “from going over the manifests and the passengers and comparing it to our databases, so far, there’s no indication that these people were terrorists. There’s no indication of terrorist chatter in the days leading up to it.”

“So, no, they’re just — nothing is being ruled in, nothing is being ruled out, and everything is being looked at exhaustively,” the congressman added.