"The DPRK agreed to disable all existing nuclear facilities subject to abandonment [in a February agreement]," a statement released in Beijing on Wednesday said, using the acronym for North Korea's official name.
The decision has been hailed by Washington as a major step towards a denuclearised Korean peninsula.
The US is to send a group of experts to North Korea within the next two weeks to oversee preparations for the shutdown.
Under a breakthrough February deal, North Korea has shut down and sealed its Soviet-era Yongbyon nuclear plant and allowed UN inspectors to visit the site in July.
Pyongyang, which conducted a nuclear test nearly a year ago and is believed to have enough plutonium to make at least eight or nine atomic bombs, has in return received shiploads of heavy fuel oil and held bilateral talks with the US that could bring the state out of diplomatic isolation.
Wednesday's statement, which followed the end of the six-party talks on Sunday, said that the disablement of the three Yongbyon nuclear facilities covered in the February deal would be completed by the end of 2007.
North Korea would also provide a "complete and correct" declaration of all its nuclear programmes by then.
Bush welcomes deal
"I welcome the agreement announced today at the six-party talks in Beijing," George Bush said in a statement.
|"I welcome the agreement announced today at the six-party talks in Beijing"|
"Today's announcement reflects the common commitment of the participants in the six-party talks to realise a Korean Peninsula that is free of nuclear weapons," Bush said.
Gordon Johndroe, the White House National Security Council spokesman, said the deal, if implemented, would end North Korea's production of plutonium.
Christopher Hill, the chief US nuclear negotiator, said about half of the aid under the deal would be in fuel oil and the rest in improvements to North Korea's electricity infrastructure and to its fuel storage capacity.