Kim Jong Un has requested a second summit with American president Donald Trump, after sending him a "warm, positive" letter. The North Korean leader wrote to Mr Trump after their historic summit in Singapore earlier this year to seek a follow up, which is being arranged. White House press secretary Sarah Sanders said: "It was a very warm, very positive letter. "The primary purpose of the letter was to schedule another meeting with the president, which we are open to and are already in the process of co-ordinating." She said the letter showed "further evidence of progress" as well as a commitment from the secretive nation to denuclearisation. It comes after a follow-up to the June summit was scuppered in August, when…