Kim Jong-un seized on Russia’s need for support in its war against Ukraine. His reward is a rapidly modernizing military that threatens the delicate balance of power on the Korean Peninsula.

North Korea has sent soldiers and millions of munitions, including missiles and rockets, to Russia over the past year, according to a new report by an international watchdog, which details the extent to which Pyongyang has helped Moscow “terrorize” Ukraine’s population over its three-year war.

The United States and 10 allies say the military cooperation between Russia and North Korea flagrantly violates U.N. sanctions and has helped Moscow increase its missile strikes on Ukrainian cities