South Korea’s president called on Pyongyang on Monday to stop raising tensions and return to talks. President Moon Jae-in said the rivals must not reverse the peace deals that he and North Korean leader Kim Jong-un agreed during summits in 2018.

Pyongyang threatened on Friday to destroy a liaison office and take unspecified military steps against South Korea. If carried out, the office’s demolition could pose a serious setback to Moon’s efforts to restore Korean reconciliation and find a negotiated solution to the North Korean nuclear issue, AP said.

“North Korea must not sever communications and create tensions to turn back the clock to a past confrontational period,” Moon said during a meeting with top presidential advisers, according to his office.

Moon met Kim three times in 2018 and was behind now-dormant diplomacy between Pyongyang and Washington, including the first summit between Kim and US President Donald Trump in Singapore in 2018.