For the past 5 days, North Korea has refused to communicate with South Korea over the two-way military liaison phone line the two countries use to communicate twice daily. The refusal to communicate coincides with a joint-military exercise between South Korea, Japan and the U.S. South Korean officials have verified that there are no technological faults in the system. Last week, North Korea issued a statement saying that the exercise was pushing the region to “the brink of a nuclear war.” The statement was issued the day after the U.S. flew nuclear capable B-52 bombers over the Korean peninsula. In addition to the flyover, the aircraft carrier USS Nimitz is conducting anti-submarine drills with South Korean and Japanese destroyers.