The same day that President Trump thanked Kim Jong Un for returning remains of Americans killed in the Korean War and sending him a “nice” letter, the US envoy to South Korea warned the rogue regime that it has to get serious about denuclearization.

Ambassador Harry Harris on Thursday called on the North to make “demonstrable moves” to get rid of its nukes before the declaration of a formal end to the Korean War, which technically has been in an armistice since 1953, the Yonhap News Agency reported.

“One of the things that hasn’t happened is the demonstrable moves toward denuclearization before we can entertain something like the end-of-war declaration,” Harris told reporters.

“We need to see the move and I haven’t seen that yet.”

The contents of Kim’s new letter to President Trump remained undisclosed, with Trump tweeting back to the despot: “I look forward to seeing you soon!”