Iran may played a role in a recent hacking attack at Sony Pictures Entertainment after the company released a film about the fictional assassination of North Korean Leader Kim Jong-Un.
The FBI believes the Iranian regime, as well as China or Russia, could have provided the highly sophisticated malware that corrupted Sony's computers, an intelligence source said.
There was also no evidence of a forced entry into the Sony systems, pointing to an insider threat or stolen credentials, and emails sent to Sony included blackmail demands unrelated to the movie, the source added.
And US officials said the attack originated outside North Korea, but believe the individuals behind it were acting on orders from the North Korean government.
US State Department Spokeswoman Jen Psaki said: "Given the destructive efforts or effects of this attack, we're treating this as a national security matter, and as such, members of the president's national security team have been in regular meetings regarding this attack."
The White House has also declined to directly blame North Korea for the attack, though Press Secretary Josh Earnest referred to the incident as a 'serious national security matter'.