Ri said the recent developments have proved that the two Koreas, if they cooperate, could improve inter-Korean relations, ease tensions and make a "breakthrough" for reunification free from outside intervention, the reports showed.

He gave credit for the current peace mood to North Korean leader Kim Jong-un, saying it is the result of the completion of the country's nuclear armament, according to the reports.

His trip to Azerbaijan appears to be part of the North's stepped-up diplomatic drive ahead of its respective summits with South Korea and the United States in April and May. The two Koreas plan to hold what will be their third summit in history at the truce village of Panmunjom on April 27.

Ri plans to travel to Russia next week to meet with his Russian counterpart Sergei Lavrov on Tuesday. He earlier met with Chinese Foreign Minister Wang Yi.

On Wednesday, a separate group of North Korean officials met with their European Union counterparts in Brussels and discussed issues surrounding the Korean Peninsula, foreign media reported.

They later met with Bulgarian officials in charge of Asia affairs. Bulgaria currently holds the EU presidency.

South Korea's foreign ministry said on Thursday that it is closely monitoring the recent diplomat activities by North Korea and called on Pyongyang to use such overseas trips as a chance to clarify its stance on the need for denuclearization and help establish lasting peace on the Korean Peninsula.