A pro-North Korean newspaper said Thursday that Pyongyang's status as a nuclear state has become "irreversible" with the recent stipulation of a nuclear force-building policy in its constitution.

In a key parliamentary meeting attended by leader Kim Jong-un last week, the North stipulated the policy of strengthening its nuclear force in the constitution, a year after it enacted a new nuclear law authorizing the preemptive use of nuclear arms and called its status as a nuclear state "irreversible."

"The status as a nuclear state has become irreversible," said the Choson Sinbo, a pro-North Korea newspaper in Japan, whose articles are considered to reflect Pyongyang's positions. "A move to advance and improve nuclear weapons will be carried out powerfully."

The newspaper said the decision made at the ninth session of the 14th Supreme People's Assembly was based on the "stern strategic assessment" that Pyongyang's status as a nuclear state should never be compromised but further strengthened.

"It is specified in Article 58 of Chapter 4 that nuclear weapons development should be advanced to guarantee the nation's right to survive and develop, suppress war and shield the peace and stability of the region and the world," it said.

The North's state media outlets, which reported on the key parliamentary meeting, had not specified in which part of the constitution the nuclear policy was stipulated.

The newspaper denounced the strengthening security cooperation among South Korea, the United States and Japan, claiming they are scaling up military provocations against the North.

It is a "mission" for a "responsible nuclear state" to accelerate the development of nuclear weapons in such circumstance, it added. (Yonhap)