N. Korea resuming nuclear activities

North Korea said Saturday that it had begun harvesting plutonium from spent fuel rods at its main nuclear plant to build up its atomic arsenal. The move, in defiance of tightening U.N. sanctions, threatened to further damage efforts to dismantle the communist nation’s nuclear program.

“This will contribute to bolstering the nuclear deterrence for self-defense in every way to cope with the increasing military threats from hostile forces,” the official Korean Central News Agency quoted a Foreign Ministry spokesman as saying Saturday.

North Korea carried out a nuclear test in 2006 and is thought to have enough weaponized plutonium to make more than half a dozen bombs. Five nations -- Russia, China, South Korea, Japan and the United States -- have been negotiating for years with North Korea on ending its nuclear weapons program, but it has walked away from the talks.

Saturday’s announcement, which could not be independently verified, came just hours after the United Nations imposed new sanctions on three North Korean companies in response to the country’s controversial rocket launch April 5.

North Korea says it sent a satellite into orbit as part of a peaceful bid to develop its space program. The U.N. Security Council called the rocket launch a violation of resolutions barring North Korea from missile-related activity, since the delivery systems for satellites and missiles are similar.

North Korea retaliated by quitting the disarmament talks and vowing to restart its atomic facilities. Officials in Pyongyang, the capital, this month expelled international nuclear monitors from the main nuclear site at Yongbyon.

With eight of 11 steps toward disablement complete at Yongbyon, experts have said it could take months to get the plant fully restarted.

Kim Yong-hyun, a professor at Seoul’s Dongguk University, called the newest move a bluff designed to pressure Washington into holding direct talks with Pyongyang outside the six-party process.

Kim predicted that the government would take further provocative steps as long as the U.S. continues to ignore it.