The U.S. is not discussing “joint nuclear exercises” with South Korea, President Joe Biden said Monday, seemingly contradicting claims from ROK President Yoon Suk-yeol that the allies may re-envision extended deterrence on the Korean Peninsula.

Yoon had earlier said in an interview with the Seoul-based Chosun Ilbo newspaper that the allies are discussing ways to enhance South Korea’s involvement in exercises related to U.S. nuclear weapons.