Pentagon confirms North Korean troops are training in Russia, may be sent to fight in Ukraine

The Pentagon has confirmed that thousands of North Korean troops are training with Russian forces at three specialized military sites inside Russia. Ukrainian President Volodomyr Zelenskyy is warning that Russia may send those forces to Ukraine and U.S. Defense Secretary Lloyd Austin calls the development a very serious escalation. Isaac Stone Fish, CEO and founder of China-focused research firm Strategy Risks, joined CBS News to discuss why the North Korean troops are in Russia and what it could mean for the world.