In its harshest rhetoric to date, North Korea is claiming that the U.S. government was behind the making of The Interview. The country is now threatening to attack the “the White House, the Pentagon and the whole U.S. mainland” if the U.S. follows through with President Obama’ statement Friday that the the States will “respond proportionally” to the cyber attack on Sony Pictures that the U.S. government said was ordered by the North Korean government in retaliation for the film.

In a statement Sunday, North Korea’s top military body, the National Defense Commission, headed by the country’s leader Kim Jong-un who was lampooned in The Interview, declared that it has “clear evidence that the U.S. administration was deeply involved in the making of such dishonest reactionary movie,” and that it has “already launched the toughest counteraction. Our target is all the citadels of the U.S. imperialists who earned the bitterest grudge of all Koreans. Whoever challenges justice by toeing the line of the biggest criminal U.S. will never be able to escape merciless punishment.”

While once again denying that it was not involved in the attack on Sony Pictures, North Korea said that it “highly esteems the righteous action” taken by the Guardians of Peace, the group claiming responsibility for the attack.

The latest rhetoric follows North Korea’s proposal yesterday to launch a joint investigation with the U.S. targeted at finding the culprit for the hack attack. It was accompanied by a threat of serious consequences should Washington D.C. fail to comply with the joint probe.