North Korea has offered to hold a joint inquiry with the United States into a cyber-attack on Sony Pictures, strongly denying US claims that it is behind it.
Its foreign ministry accused the US of "spreading groundless allegations", which it said a joint inquiry would refute, the BBC reported.
Without addressing Pyongyang's idea, a US spokesman insisted North Korea must admit "culpability".
The attack and subsequent threats against cinemas led Sony to cancel the release of a satirical film, The Interview. The comedy's plot includes a fictional plan to kill Kim Jong-Un.
The film had been due to open on Christmas Day. However, after anonymous threats against cinemas, Sony said it was considering releasing it "on a different platform".
The FBI said on Saturday that North Korea had carried out last month's cyber-attack, in which script details and private emails were leaked.
A group calling itself Guardians of Peace (GOP) had taken credit for the attack.
A news presenter read out a response from North Korea's government on state television:
"If the US refuses to accept our proposal for a joint investigation and continues to talk about some kind of response by dragging us into the case, it must remember there will be grave consequences."
The US has defended its findings, saying it was confident the North Korean government was "responsible for this destructive attack".
"If the North Korean government wants to help, they can admit their culpability and compensate Sony for the damages this attack caused," US National Security spokesman Mark Stroh said.
Reuters reports that the White House said it was consulting with Britain, Australia and New Zealand, among other countries, over the cyber attack.
It said it was hoping to organise an international response to the attack.
The movie features James Franco and Seth Rogen as two journalists who are granted an audience with Mr Kim. The CIA then enlists the pair to assassinate him.
The film's cancelled release drew criticism in Hollywood, with some calling it an attack on freedom of expression.
Actor George Clooney told the trade website Deadline on Friday the film should be released online, saying Hollywood should not be threatened by North Korea.