Seoul:North Korea fired a submarine-launched ballistic missile off its east coast on Saturday but it failed in its initial flight stage, South Korea's military said. The missile was fired from waters southeast of the coastal port city of Sinpo, South Hamgyong province, Yonhap news agency quoted the military as saying. "The SLBM was ejected from the submarine normally, but the initial flight was unsuccessful," it said. The military also said that it strongly denounced such provocative acts by North Korea. The missile flew only a few kms before the presumed explosion, it said. The launch came a day after Seoul and Washington's announcement to deploy THAAD, a high-tech US air defence system, in South Korea.