Investigators in Malaysia are voicing skepticism that the Malaysian airliner which disappeared early Saturday was the target of an attack, say U.S. and European government sources close to the probe.
Neither the Malaysian agency leading the investigation locally, Special Branch, nor spy agencies in the United States and Europe have ruled out the possibility that militants were involved in downing the aircraft, which suddenly disappeared while flying at 35,000 feet en route from Kuala Lumpur to Beijing.
However, Malaysian authorities have indicated that the evidence so far does not strongly back an attack as a cause and that mechanical or piloting problems could be explanations for the apparent crash, the U.S. sources said.
One U.S. source said that one of the main reasons Malaysian authorities were leaning away from the theory that the plane was attacked is because electronic evidence indicates it may have made a turn back towards Kuala Lumpur before it disappeared.
However, even that information has not been clearly confirmed, and investigators and intelligence sources say the fate of the plane is still shrouded in mystery.
"There is no evidence to suggest an act of terror," said a European security source, who added that there was also "no explanation what's happened to it or where it is."
The Malaysian Special Branch is exchanging information with U.S. intelligence and law enforcement agencies, the sources said.
A law enforcement official said that the FBI, which stations agents, known as legal attaches, in U.S. embassies overseas, was in touch via those agents with authorities in both Kuala Lumpur and Beijing.
Two U.S. government agencies responsible for aviation safety, the National Transportation Safety Board and the Federal Aviation Administration, and Boeing, manufacturer of the missing aircraft, have sent officials to Kuala Lumpur to assist in the investigation if requested.
However, the FBI has not sent a special team of investigators to Asia because it has not been asked to do so and because it has not been determined that a crime occurred.
"We continue to closely monitor the situation...and stand ready to assist if needed," said FBI spokesman Paul Bresson.
U.S. security sources said that the only threats or claims of responsibility related to the presumed crash which have surfaced thus far have been deemed not credible. The fact that two passengers were traveling on stolen passports, and other passengers booked on the flight reportedly failed to turn up, is not regarded as being evidence of a possible attack, they said.