A diplomatic source in Moscow says six-way working level talks on North Korea's nuclear weapons program will open in Beijing next month.

Russia's Itar-Tass news agency quoted the source as saying that the working-level discussions, originally slated to be held this month, have been delayed until next month due to various reasons.

The source said despite the progress made in the third round of six-party nuclear talks in Beijing last month, it will not be easy to reap substantial results in a fourth round of multilateral discussions since the sensitive issue of a possible North Korean nuclear freeze would top the talks' agenda.

The source said that the working-level talks will have to produce a unified approach on the substantial issues that should be addressed in the first stage of de-nuclearizing the North's atomic weapons programs.