U.S. expects North Korea to shut reactor in 3 weeks

"We do expect this to take place soon, and within probably three weeks, I don't want to be pinned down on precisely the day," he said after talks with his Japanese counterpart, Kenichiro Sasae.

An IAEA delegation is due in North Korea on Tuesday to help draw up plans for the reactor shutdown.

Hill said that in North Korea he had also raised the issue of Japanese citizens kidnapped decades ago by Pyongyang, a highly emotive issue that prompted Tokyo to refuse to provide aid under the February 13 accord until it saw progress.

The U.S. diplomat said he had received no new answers on the fate of the abductees, seized to help train North Korean spies, but added: "I think any time you can meet DPRK officials and raise the abduction issue, it's good."

Easing Tokyo's stance on Pyongyang could be tough for Prime Minister Shinzo Abe ahead of an election expected in July.

A North Korean Foreign Ministry spokesman quoted by state media said that, during Hill's visit, both sides had agreed to consider resuming the six-party talks in the first half of July.

Hill cautioned that closing the nuclear facility was just the start of the process and "does not solve all our problems".

(Additional reporting by Isabel Reynolds in Tokyo and Jack Kim in Seoul)