South Korea's Moon: 'Too early to be optimistic' on North

"We are only at the starting line," Moon told political party leaders after his envoys revealed Kim Jong Un's offer following their return from a historic trip to Pyongyang.

He denied allegations of a behind-the-scenes agreement with Pyongyang in return for it coming to the negotiating table.

"There has been no backroom deal whatsoever with the North," Moon was quoted as saying by a spokesman of the minor opposition Bareunmirae Party.

"There will be no such a thing as a gift to the North," Moon added.

The South's leader stressed the importance of maintaining close co-operation with the US, its security guarantor, adding: "I think denuclearisation talks will become feasible only when South Korea and the US take common positions" on the issue.

There would be no let-up in sanctions or pressure purely as a result of inter-Korean dialogue, he said.

"Inter-Korean talks won't be enough to achieve peace."