North Korea has sent an "ultimatum" to the U.S. government regarding its nuclear program, a Japanese mouthpiece for Pyongyang claims.

The Chosun Sinbo daily said North Korea "reviewed the history of summits between [Pyongang] and the U.S. and sent an ultimatum on the nuclear issue to the U.S." The paper did not mention when and how the ultimatum was sent.

A statement by the North Korean Foreign Ministry in July last year claimed that the U.S. was behind a failed attempt to blow up a giant statue of Kim Il-sung and threatened to re-launch its nuclear program.

In August last year, it threatened that its capability to deter nuclear weapons is being "modernized and expanded beyond the imagination of the U.S."