Trump met Kim three times: in Singapore in 2018, in Hanoi in 2019, and in the Korean Demilitarized Zone in 2019. Trump became the first sitting U.S. president to meet a North Korean leader or to set foot in North Korea. Trump also lifted some U.S. sanctions against North Korea. However, no denuclearization agreement was reached, and talks in October 2019 broke down after one day. While conducting no nuclear tests since 2017, North Korea continued to build up its arsenal of nuclear weapons and ballistic missiles.