The attack ended a two-month pause in missile strikes on Kyiv, which had only been hit by Russian drones during that period.

The United States is concerned by Russia's growing relationship with North Korea and by what technology the two countries may be exchanging, the top U.S. arms control official said on Wednesday.

North Korean troops have begun engaging in combat operations alongside Russian forces, the U.S. State Department said on Tuesday, expressing concern that Russia had turned to North Korea for soldiers to fight in its war with Ukraine.

The treaty underscores a strengthening of military ties between Pyongyang and Moscow while geopolitical tensions rise.