An explosion-like earthquake felt around the globe has led many to believe that North Korea conducted a nuclear test on Tuesday.
Although Pyongyang had been threatening to conduct such a test for weeks, they did not confirm that it did in fact conduct such a test. Following the quake, the South Korean Defense Ministry raised their military alert level and was still trying to figure out if such a test had been conducted.
If the test was conducted, it would be another challenge to the United Nations Security Council, which recently imposed sanctions against Pyongyang for a long-range missile test. In wake of that rocket launch in December, the U.N. Security Council ordered North Korea to respect a ban on nuclear tests or they would be met with "significant action" by the U.N.