Story highlights Top UN envoy Jeffrey Feltman visited North Korea last week

He calls for an "urgent need to prevent miscalculations"

(CNN) Tensions on the Korean Peninsula are the world's most dangerous security issue, and must be resolved fast and diplomatically to avoid war, a top United Nations envoy said after a rare visit to North Korea.

Jeffrey Feltman, the UN under-secretary-general for political affairs, visited the reclusive nation between Tuesday and Friday, the first trip there by a top UN official in six years.

During his visit, he met with Ri Yong Ho, the North Korean minister for foreign affairs. Their meeting came at a particularly tense time -- a week after North Korea tested an advance long-range missile and South Korea conducted military drills with its ally, the United States.

Ri and Feltman "agreed that the current situation was the most tense and dangerous peace and security issue in the world today," the UN said in a statement

Feltman stressed the need for relevant Security Council resolutions to be implemented, saying a diplomatic solution could be achieved through sincere dialogue.