The Democratic People's Republic of Korea (DPRK) said on Tuesday that it has decided to restart facilities at the Nyongbyon nuclear comlex, which had been "mothballed and disabled" under an agreement at the six-party talks in October 2007. The complex is located 130 km north of the capital Pyongyang.

The DPRK started nuclear research as early as the late 1950s. In the mid-1960s, it established at Nyongbyon a nuclear research base with the help of the former Soviet Union and trained a great number of nuclear specialists.

A Soviet-imported 800-kilowatt reactor was then set up at Nyongbyon, enabling the DPRK's nuclear research capacity to take its initial shape. Nyongbyon has hence became the country's major site of nuclear industry.

The construction of the Nyongbyon graphite-moderated reactor started in 1980 and it went into operation in 1987. It is capable of extracting plutonium, an essential raw material for making nuclear weapons, from spent nuclear fuel rods.

The nuclear issue on the Korean Peninsula escalated in the early 1990s. The United States signed with the DPRK an framework agreement in Geneva in October 1994, promising to provide Pyongyang with two relatively proliferation-resistant light-water reactors in exchange for the suspension of the Nyongbyon nuclear complex. Afterwards, Pyongyang said it had frozen 8,000 fuel rods of the Nyongbyon reactor.

On Dec. 22, 2002, however, the DPRK restarted the operation of the nuclear complex after accusing the United States of failing on its commitments.

In August 2003, China helped bring officials from China, the DPRK, the South Korea, the United States, Japan and Russia to the negotiating table for the six-party talks.

On July 15, 2007, the DPRK announced shutting down the Nyongbyon nuclear complex.

On June 27, 2008, the DPRK destroyed the cooling tower at its Nyongbyon nuclear complex, marking a symbolic step forward towards denuclearization on the Peninsula.

On April 13, 2009, the UN Security Council adopted a presidential statement on the DPRK's rocket launch on April 5 of that year, saying it is "in contravention of Security Council resolution 1718" and urging the early resumption of the six-party talks.

Pyongyang thus announced quitting the six-party talks on nuclear disarmament and would restart nuclear facilities in protest of the UN statement.