The DPRK agreed to start the disablement of its nuclear facilities in exchange for energy assistance from other related parties, said Lim Sung-nam, South Korea's representative at a working-group's talks at the inter-Korean border village of Panmunjom.

"We had very productive and specific technical discussions," Lim said.

"The sides reached an unofficial understanding that the promised energy assistance equivalent to 950,000 tons of heavy fuel oil will be provided in the form of 450,000 tons of heavy oil and other assistance equivalent to 500,000 tons of heavy oil," Lim said.

Representatives from China, the United States, the DPRK, South Korea, Russia and Japan launched the two-day working-group talks at Panmunjom Monday.

The DPRK sparked world alarm in October 2006 by testing its first nuclear weapon. But it agreed in February to declare and disable its nuclear programs in return for 1 million tons of heavy fuel oil or equivalent energy aid.

After it shut down its nuclear reactor and other plants in July, South Korea sent an initial 50,000 tons of oil.