South Korea’s leading conservative candidate for president in next year’s elections said Friday that he does not support an end-of-war declaration between the two Koreas, breaking from the current Moon Jae-in administration under which he previously served as chief prosecutor.

Speaking at a press conference, Yoon Seok-youl said there would be “big side effects” to formally ending the Korean War, arguing that North Korea’s ongoing nuclear arms buildup does not provide a fit environment for any legally binding peace treaty.