U.S. national security adviser John Bolton has canceled his plan to visit South Korea to discuss Pyeongyang's nuclear program... ahead of the second North Korea-U.S. summit.<br />Bolton's spokesman said Friday local time... that the national security adviser has decided to stay in Washington to focus on events unfolding in Venezuela,... where the military faces a pivotal decision on whether to allow the inflow of foreign aid.<br />Though his pre-summit trip has been cancelled,... Bolton is still expected to attend the summit in Hanoi next week. <br />
