U.S. President Joe Biden called North Korea’s nuclear program a “serious threat” to global security on Wednesday, vowing to leverage both diplomacy and his relationship with American allies to solve the problem.

“On Iran and North Korea, nuclear programs present serious threats to American security and the security of the world,” Biden said during a wide-ranging speech that also covered climate change, gun control and COVID-19. “We are going to be working closely with our allies to address the threats posed by both of these countries through diplomacy as well as stern deterrence.”