North Korea has once again denied that it was behind the cyber-attack on Sony Pictures after the FBI announced on Friday that the country was “responsible” for the hack.

Instead, it’s offering to launch a joint investigation with the U.S. into the hacking attack, warning of “serious consequences” if the proposal is rejected, the Associated Press reports.

The message, which was carried by Pyongyang’s official state-run news service, comes on Saturday following President Barack Obama’s statement on Friday that the U.S. would retaliate for the attack, responding “in a place and manner and time that we choose.”

“The U.S. should bear in mind that it will face serious consequences in case it rejects our proposal for joint investigation and presses for what it called countermeasures while finding fault with (North Korea),” an unidentified North Korean Foreign Ministry spokesman said.

“We have a way to prove that we have nothing to do with the case without resorting to torture, as the CIA does,” he added before noting that the U.S. is slandering Pyongyang as it lacks sufficient evidence that ties it to the hacking.

The FBI said it based its conclusion on the fact that “technical analysis of the data deletion malware used in this attack revealed links to other malware that the FBI knows North Korean actors previously developed. For example, there were similarities in specific lines of code, encryption algorithms, data deletion methods and compromised networks.”

On Friday, President Obama declared that Sony “made a mistake” in pulling “The Interview,” a comedy whose plot revolves around an assassination attempt on North Korean leader Kim Jong-un.

“I wish they had spoken to me first. … We cannot have a society in which some dictator someplace can start imposing censorship,” Obama said at the news conference, referring to Sony execs.

Sony Pictures Entertainment chairman Michael Lynton later said the studio “had no choice” but to cancel the Christmas release of “The Interview.”