The DPRK says it has begun reprocessing spent fuel rods in a pilot atomic power plant.
The DPRK's Foreign Ministry made the announcement hours after the UN imposed new sanctions on the country for its recent rocket launch.
A DPRK official said on Saturday that the country has restarted its nuclear facilities to harvest weapons-grade plutonium.
The DPRK says the reprocessing will help bolster nuclear deterrence for self-defense to cope with increasing military threats from hostile forces.
Earlier in the day, the UN sanctions committee announced it was targeting three major DPRK companies for new sanctions, alleging they had links to the country's military activities.
The UN Security Council's recent presidential statement had called for an adjustment of sanctions against the DPRK after its April fifth rocket launch.
Yukio Takasu, Japanese Ambassador to UN, said, "Sanction committee on North Korea has made a very important decision and Japan, as a key country for interest in this issue, is very pleased that sanction committee made an extraordinary effort. "
The DPRK said the sanctions violate the United Nations charter and that the country has a right to launch satellites.
Pak Tok Hun, DPRK Ambassador to UN, said, "It is inalienable rights of every nation and country to make peaceful use of outer space. That's why we totally reject and do not recognize any sorts of decision which has been made, or would be made, in the security council."
The announcement of the sanctions are likely to draw further protests from the DPRK. Last week it expelled international nuclear monitors, vowed to restart its nuclear programme and quit the six-party talks.
(CCTV April 26, 2009)