SEOUL, South Korea — North Korea's threat to restore its nuclear facilities should not be seen as "empty talk" and the standoff could develop into a crisis similar to the country's first atomic test, a pro-Pyongyang newspaper said Wednesday.

The report came one day after North Korea's Foreign Ministry announced it has stopped disabling its nuclear reactor and other plutonium-producing facilities because the United States failed to remove the communist nation from Washington's terrorism blacklist.

North Korea also warned that it would consider reversing what it has done to roll back its nuclear programs under a landmark disarmament-for-aid deal reached in international nuclear talks last year.

The Japan-based Choson Sinbo newspaper, considered one of North Korea's overseas propaganda outlets, reported from Pyongyang on Wednesday that the North's warning should be taken seriously.

The North's statement "must not be empty talk. If the United States moves on a road to intensify confrontation with the North ... it may lead to a situation where the hands of the denuclearization clock may run backward," the paper said on its Web site monitored in Seoul.

"There is no guarantee that the same situation in which (the North) was forced to conduct the nuclear test would not be created," it said.

The report did not cite any North Korean officials.

North Korea carried out an underground nuclear test blast in October 2006.

North Korea began disabling its plutonium-producing nuclear reactor and other facilities at its Yongbyon nuclear center in November as a step toward their ultimate dismantlement in exchange for economic aid and political concessions, including removal from the U.S. terror list.

It was the first time that the North has halted the disablement work, though it had slowed the process in protest against the delayed provision of promised aid from its negotiating partners.

The United States announced in June that it would take the North off the terror list after Pyongyang turned in a long-delayed account of its nuclear programs and blew up the cooling tower at the reactor.

The two sides have since been negotiating how to verify the nuclear declaration, but no agreement has been reached. Washington has insisted it will remove the North from the terror list only after the country agrees to a fully verification plan.

The United States reacted calmly to the North's latest threat.

Secretary of State Condoleezza Rice said the North "still has obligations" and that discussions with the North were continuing. The State Department also said U.S. officials were still at the Yongbyon nuclear reactor monitoring the sites.

South Korea and Japan have expressed regret and concern over the North's decision and Russia joined in Wednesday, saying it evokes "disappointment and concern" and urged Pyongyang to reconsider.

Meanwhile, Seoul's Unification Ministry, in charge of relations with the North, said Wednesday the government would not link the nuclear tension to its consideration over whether to provide the North with humanitarian aid.

The U.N.'s World Food Program has asked South Korea to provide emergency aid to the North to help it avert a food crisis, and the government has not announced whether to accept the appeal.

Relations between the two Koreas have chilled rapidly since the South's conservative President Lee Myung-bak took office in February, and Pyongyang protested his hard-line stance on the North.