South Korean President Lee Jae Myung called for efforts to secure a moratorium on North Korea’s production of nuclear materials through talks on Monday, as Chinese leader Xi Jinping visits Pyongyang for a summit with Kim Jong Un.

Lee made the remarks in response to questions about Seoul’s approach to denuclearization at a press conference marking the first anniversary of his inauguration, which largely focused on the outcome of the June 3 local elections and the economy.

“While President Xi is visiting North Korea, and while Russia and North Korea are drawing closer militarily — making the inter-Korean border sharper,