Inspectors from the UN nuclear watchdog are back in North Korea, resealing nuclear facilities after Washington took Pyongyang off its terrorism blacklist, the US State Department said on Tuesday.

"I understand that the IAEA has resumed its work. It has started to reapply seals," said State Department spokesperson Sean McCormack, referring to the International Atomic Energy Agency.

"I think, as simply put, the North Koreans have started the reversal of their reversal," he said. "They're getting back to that baseline where they were very close to meeting their obligations ... in terms of disablement."

The IAEA said on Monday that North Korea had granted its inspectors access to its nuclear facilities at Yongbyon, including its power plant, fuel fabrication plant and reprocessing facility.

It added that, from Tuesday, "core discharge activities at the reactor would be resumed, monitored by agency inspectors".

Yongbyon was shut down in July 2007 under an aid-for-disarmament deal agreed by North Korea, South Korea, the United States, Russia, China and Japan after Pyongyang staged its first nuclear weapons test in October 2006.

North Korea threatened to reverse the process, however, if Washington refused to take it off its blacklist of state sponsors of terrorism — which it did on Saturday, despite Japanese reservations .

AFP