WASHINGTON, Dec. 17 (UPI) -- U.S. officials believe those responsible for hacking into Sony Pictures were working under the direction of the North Korean government, several media organizations reported Wednesday.
Sources with direct knowledge of a U.S. government investigation into the security breach told the Wall Street Journal it is believed a North Korean government hacking team known as Unit 121 is behind the attack. The sources were not identified.
CNN, also quoting unnamed sources, reported that an official announcement is expected Thursday blaming the Pyongyang-based group called Bureau 121.
The news came Wednesday evening after Sony Pictures said it plans to postpone the theatrical release of The Interview, the Seth Rogen and James Franco comedy that prompted the cyberattack earlier this month.
The film focuses on a plot to kill North Korean leader Kim Jong Un.
President Barack Obama said the cyberattack -- which resulted in the release of Sony Pictures personnel information and executive emails -- was "very serious."
"We're investigating, we're taking it seriously," Obama said during an interview with ABC News. "We'll be vigilant. If we see something that we think is serious and credible, then we'll alert the public."
"For now, my recommendation would be that people go to the movies," he said.