North Korea has developed a long-range submarine missile with a shooting range exceeding 2,500 km (1,554 miles). The missile is heavily-modified version of the old Soviet Union R-27 (named SS-N-6 by NATO) and can be placed on a submarine or other movable platform. The news comes days after an unknown missile was filmed flying from the sea off the coast of California. Military officials officially claim they do not know who fired the missile, but speculation based on recent events indicates that it may have been a show of strength from North Korea.