The White House said Monday that U.S. President Donald Trump has received a letter from North Korean leader Kim Jong-un calling for a second summit and coordination for the meeting is already underway.

White House spokeswoman Sarah Sanders said in a news briefing that Kim requested the follow-up to the historic Singapore summit in June in a “warm, very positive letter” to Trump delivered in recent days.

Sanders said the White House would not release a copy of Kim’s letter without Pyongyang’s permission, but its primary purpose was to schedule another meeting with Trump.

She added that Washington is open to a second summit and talks are already underway to coordinate it. 

Amid stalled negotiations to dismantle the regime's nuclear weapons program, Trump said last week that he was expecting a letter from Kim.