The United States is sending FBI agents and experts to help investigate the disappearance of a Malaysia Airlines jet.
According to the Los Angeles Times newspaper, FBI agents will help review video from the Kuala Lumpur airport for images of departing passengers that can be checked in the bureau's vast counter-terrorism database.
At least three US citizens, and an infant who could be a US citizen, were on board the plane.
"This gives us entree" to the case, the official told the LA Times, speaking on condition of anonymity.
The disclosure that two people on board were travelling on stolen passports has raised questions about a possible terrorist attack, but US intelligence officials earlier told US media that stolen passports "don't necessarily say to us that this was a terrorism act".
The Malaysian Airlines Boeing 777 was carrying 227 passengers, including six Australians and two New Zealanders, as well as 12 crew members when it disappeared on Saturday during a flight from Kuala Lumpur to Beijing.
