Full six-party negotiations on disarming North Korea could resume within months, Interfax cited Russia's foreign ministry as saying Friday, following Yongbyon's partial demolition of a nuclear plant.

The six parties – North and South Korea, Japan, Russia, China and the United States – are expected to meet in Beijing early next month at delegation level to discuss ways to verify the North's denuclearisation efforts.

A full ministerial meeting of the Six "could take place within the next two months", the news agency quoted the foreign ministry's press service as saying.

North Korea on Friday blew up the cooling tower of its atomic reactor to demonstrate its commitment to nuclear disarmament, a day after handing over details of its atomic programmes.

TV footage showed the 30-metre (99-foot) tower engulfed in a huge cloud of smoke as a landmark piece of the country's nuclear history collapsed in ruins.

"It was a significant and very important step," US State Department official Sung Kim told a reporter at the scene. "As I saw it, it was a complete demolition."

The cooling tower at Yongbyon, 96 kilometres (60 miles) north of Pyongyang, was the most visible symbol of the communist state's decades-old pursuit of nuclear weapons.

It produced the plutonium for a programme which culminated in a nuclear test in October 2006.