Washington - North Korea is again making progress in dismantling its nuclear facilities after the United States and North Korea broke an impasse last week over the denuclearization of the Korean peninsula, the US and South Korea said Friday.

US Defence Secretary Robert Gates and South Korean Defence Minister Lee Sang Hee in a joint statement welcomed the process being brought back on track and warned that freeing the Korean peninsula from nuclear weapons was key to security in the region.

"The North Korean nuclear and conventional threat continues to be the focal point of our deterrent and defense posture," Gates later told reporters, reiterating the US promise to protect South Korea from attack after an annual meeting review of South Korean-US defence relations in Washington.

The meeting and nuclear developments come amid rumours over the deteriorating health of North Korea's long time leader Kim Jong Il, who is said to be recovering from a stroke or brain surgery and has not been seen in public in two months.

US and South Korean intelligence suggested Kim was still in control of his administration, South Korea's Lee said. Both countries were closely monitoring the situation to avoid any instability on the peninsula, he said.

State Department spokesman Sean McCormack said North Korea has reversed steps taken in the last weeks to restart its nuclear reactor at Yongbyon and was allowing monitoring equipment back into its nuclear facilities, meeting its part of a verification deal after the US agreed to remove North Korea from its list of state terrorism sponsors.

"The North Koreans have ... reversed all their reversals in the reactor, all the seals are back on, the surveillance equipment is back reinstalled, and the equipment that had been removed is back where it had been," McCormack told reporters, citing US monitors on the ground in North Korea.

McCormack said the North Koreans had gone further in dismantling the Yongbyon reactor than they were before the impasse began. He said the process had slowed on separate fuel reprocessing facilities at Yongbyon, but progress was being made.

North Korea agreed to abandon its nuclear weapons programme in a 2007 pact produced by six-nation talks that also include China, Japan, Russia and South Korea.

But the agreement was on the verge of collapse last month when North Korea resumed activities at its main nuclear facility Yongbyon and earlier this month banned the UN nuclear agency, the International Atomic Energy Agency, from inspecting the site.

McCormack said the six-nation talks would resume shortly and the countries were likely to approve the verification plan agreed to by the US and North Korea last week. A fixed date for the meeting was to be announced soon by the Chinese, who chair the talks. (dpa)