Foreign Minister Song Min-soon says efforts to resolve the North Korean nuclear problem are at a critical juncture.

In a lecture hosted by the Korea Chamber of Commerce and Industry, he voiced concerns over the slow progress in the North's disclosure of its nuclear activities.

He said that countries concerned aim to persuade Pyongyang to declare and disable its nuclear programs by year’s end.

The communist country pledged to do so in the latest six-party agreement reached in October.

But Song added the parties should be flexible with that timetable if the North misses the deadline.

He urged North Korea to stick to its denuclearization pledges, noting that the U.S. is preparing to remove the North from its terrorism blacklist as a reward.