A North Korean envoy arrived in Washington on Thursday for expected talks with Secretary of State Mike Pompeo and a possible encounter with President Donald Trump aimed a laying the groundwork for a second US-North Korea summit. The envoy arrived on the same day Trump unveiled a revamped US missile defense strategy that singled out North Korea as an ongoing and “extraordinary threat,” seven months after he declared after his first summit with leader Kim Jong Un that the North Korean threat had been eliminated. Kim Yong Chol, Pyongyang’s lead negotiator in denuclearisation talks with the United States, was due to meet Pompeo and could also go to the White House on Friday, a person familiar with the plan said, a sign of potential movement in a diplomatic effort that has appeared stalled for months. The North Korean visit could yield an announcement of plans for another summit between Trump and Kim Jong Un, the source said, speaking on condition of anonymity. There has been no indication, however, of any narrowing of differences over US demands that North Korea abandon a nuclear weapons program that threatens the United States or Pyongyang’s demand for a lifting of punishing sanctions. Kim Yong Chol, a hardline former spy chief, arrived in…