WASHINGTON (AP) - The US is closely watching North Korea for signs of a possible missile launch or nuclear test in the coming days that officials are referring to as a "Christmas surprise." A significant launch or test would mean the end of North Korea's self-imposed moratorium and raise tensions in the region. It would also be a major blow to one of the Trump administration's major foreign policy initiatives: the drive to get North Korea back to negotiations to eliminate its nuclear weapons and missiles.