SEOUL — North Korea said Tuesday that it would put all its nuclear facilities — including its operational uranium-enrichment program and its reactors mothballed or under construction — to use in expanding its nuclear weapons arsenal, sharply raising the stakes in the standoff with the United States and its allies.
The announcement by the North’s General Department of Atomic Energy came two days after the country’s leader, Kim Jong Un, said his nuclear weapons were not a bargaining chip and called for expanding his country’s nuclear arsenal in ‘‘quality and quantity’’ during a meeting of the Central Committee of the ruling Workers’ Party of Korea.
The decision will affect the role of the North’s uranium-enrichment plant in the North’s main nuclear complex in Yongbyon, north of the capital, Pyongyang, a spokesman for the nuclear department told the Korean Central News Agency. It was the first time North Korea said it would use the plant to make nuclear weapons. Since first unveiling it to a visiting US scholar in 2010, North Korea had insisted that it was running the plant to make reactor fuel to generate electricity.
Saying ‘‘work will be put into practice without delay,’’ the spokesman also said North Korea would refurbish and restart its mothballed nuclear reactor in Yongbyon. The five-megawatt graphite-moderated reactor had been the main source of plutonium bomb fuel for North Korea until it was shut down under a short-lived nuclear disarmament deal with the United States in 2007.
North Korean engineers are believed to have extracted enough plutonium for six to eight bombs — including the devices detonated in 2006 and 2009 in underground nuclear tests — from the spent fuel unloaded from the reactor.
It is unknown whether North Korea’s third nuclear test in February used some of its limited stockpile of plutonium or fuel from its uranium-enrichment program, whose scale and history remain a mystery.
Kim has recently raised tensions with threats to attack the United States and South Korea with preemptive nuclear strikes. But this week, he appeared to shift his tone slightly by reiterating that his nuclear weapons were a deterrent that helped his country focus on the more pressing domestic issue of rebuilding the economy.
Even so, a restarting of the reactor and weapons-producing role for its uranium-enrichment plant would add to growing US concern over the North’s nuclear weapons program. The developments mean that the North would now have two sources of fuel for atomic bombs — plutonium and highly enriched uranium — and that Kim could become more strident in his demands.
In Beijing, the spokesman for the Foreign Ministry, Hong Lei, said China, the North’s main ally, felt ‘‘regretful’’ about the North’s announcement.
“We have noticed the statement made by the DPRK and feel regretful about it,’’ Hong said Tuesday at a daily briefing with reporters, using the North’s official name, the Democratic People’s Republic of Korea. China urges all parties ‘‘to remain calm and restrained,’’ he said.
The UN secretary general, Ban Ki-moon, said Tuesday that North Korea appears to be ‘‘on a collision course with the international community,’’ the Associated Press reported. Speaking in Andorra, where he is on an official visit, Ban said the crisis had gone too far and international negotiations were urgently needed.
China’s official Xinhua news agency issued comments from Deputy Foreign Minister Zhang Yesui that did not expressly single out North Korea but nonetheless signaled deepening worry about its actions and the response from the United States and its allies.
Zhang told Xinhua that he had met with diplomats from the countries concerned and ‘‘expressed grave concern over current developments.’’ The report did not identify those countries.
Moving swiftly upon the party’s ‘‘new strategic line,’’ the country’s atomic energy department said measures were being taken to expand the North’s nuclear deterrent, as well as to build an indigenous nuclear power industry to resolve the country’s acute electricity shortage. The North’s rubber-stamp Parliament, the Supreme People’s Republic, enacted a new law Monday on ‘‘consolidating the position of nuclear weapons state,’’ official media reported Tuesday.
North Korea ‘‘shall take practical steps to bolster up the nuclear deterrence and nuclear retaliatory strike power both in quality and quantity to cope with the gravity of the escalating danger of the hostile forces’ aggression and attack,’’ the law said. It also said North Korea shall cooperate for ‘‘nuclear nonproliferation,’’ depending on ‘‘the improvement of relations with hostile nuclear weapons states.’’
The North’s new party line removed any lingering ‘‘ambiguity’’ over what it might try to do with its nuclear weapons, said a senior South Korean government official, who briefed a group of foreign reporters on on condition that he remain unnamed.