Leading North Korea expert Andrei Lankov tells Fox News he is “90 percent sure” Pyongyang was behind the hacking attack on Sony for its production of “The Interview.”

"It is in their style," the Seoul-based scholar said. 

Lankov cited a recent hacking attack on banks and media in South Korea. They were hacked reportedly with a similar computer code used in the Sony cyberattack. There were also threats of “obliteration” against the South Korea firms. South Korean investigators confirmed it was Pyongyang.

This comes after a law enforcement source told Fox News the FBI had connected the hack attack with North Korea hours after Sony announced it had scrapped the Dec. 25 release of the movie.

This week North Korea’s state-run media KCNA endorsed the Sony hacking saying it was done by “sympathizers.” Lankov says this is as close to an endorsement as possible.

Another expert noted “ambiguity of attribution and guerilla-warfare approach” are the tactics of North Korea.

Fox News has also been told, however, there was “zero” chance there would have been any actual attacks on theaters.”

"Sony was stupid to make a move about killing Kim Jung-Un," Andrei Lankov said, "but it was even more stupid to cave into pressure." 

The expert concluded it will be seen that America is vulnerable to blackmail and North Korea will try it again.

In an interview with ABC News aired Wednesday, President Obama encouraged Americans to go to the movies.

The Obama administration is expected to call out North Korea Thursday on the attack.

The Sony hacking saga took a sinister turn on Tuesday when hackers sent a message threatening to target theaters showing “The Interview” in a 9/11 type attack.

Sony then told theaters they will not be penalized should they choose not to show it.

A representative for the FBI Los Angeles Field Office told FOX411 that the bureau is “aware of the recent threats and continues to work collaboratively with our partners to investigate.”

Security experts told Fox that in the wake of the Sydney siege and the release of the CIA enhanced interrogation report last week, it was crucial the threat be taken seriously by authorities.

“This threatening statement obviously has some foundation and may be linked to current global hostilities towards the west and predominantly the U.S.,” said Lee Oughton, global security and risk management expert. “We are still unaware how deep the hackers were able to penetrate into the Sony systems. Only time will tell how much information they were able to ascertain and what price Sony will pay in the international market.”

Actors James Franco and Seth Rogen already canceled all media appearances promoting their film.

Fox News' Greg Palkot, Lucas Tomlinson and Hollie McKay and the Associated Press contributed to this report