Rome, March 18 - North Korea defied U.N. resolutions by firing a medium-range ballistic missile into the sea on Friday, Seoul and Washington officials said, days after its leader Kim Jong Un ordered weapons tests linked to its pursuit of a long-range nuclear missile capable of reaching the U.S. mainland, according to the Associated Press. South Korea's Joint Chiefs of Staff said in a statement that the missile fired from a site north of Pyongyang flew about 800 kilometers (500 miles) before crashing off the North's east coast. The Joint Chiefs of Staff said it wasn't known what type of missile was fired, but a South Korean defense official, requesting anonymity citing department rules, said it is the first medium-range missile launched by the North since April 2014 when it fired two. Tensions remain high on the Korean peninsula.