The treaty raises the risk of confrontation in the region and could prompt the United States and its allies to bolster their military presence on China’s periphery.

Kim and Putin touted the "Treaty on C omprehensive Strategic Partnership " as a breakthrough for Moscow-Pyongyang ties, according to North Korean state media. South Korean National Security Director Chang Ho Jin in a news conference expressed "grave concern" over the deal.

Both Russian President Vladimir Putin and North Korean leader Kim Jong Un say a new strategic partnership is a breakthrough, but what it means for their relationship is still uncertain.