SEOUL, South Korea (AP) — South Korean President Moon Jae-in said Friday he is pushing for "irrevocable progress" in efforts to rid North Korea of its nuclear weapons by the end of this year as he prepares for his third summit with North Korean leader Kim Jong Un.

Meanwhile, U.S. President Donald Trump said he was expecting to get a "positive" letter from Kim after South Korean special envoys traveled to Pyongyang this week to help resolve the nuclear stalemate and pave the way for the Sept. 18-20 Moon-Kim summit.

South Korean officials say the summit in Pyongyang will focus on how to achieve...