SEOUL -- The Democratic People's Republic of Korea (DPRK) fired what is estimated to have been a submarine-launched ballistic missile (SLBM), South Korea's Yonhap news agency reported on Saturday.

The projectile was launched in waters southeast of the DPRK's eastern port city of Sinpo in South Hamgyong province, South Korea's Joint Chiefs of Staff (JCS) was quoted as saying.

The military is analyzing the exact flight distance of the projectile and whether the test-firing was successful.

If confirmed, it would mark the DPRK's first test-launch of its SLBM since April 23 when a ballistic missile launched from a submarine flew about 30 km before exploding into fragments.

The launch came a day after Seoul and Washington jointly announced their decision to deploy the Terminal High Altitude Area Defense (THAAD) in the US Forces Korea (USFK) to better tackle what they claimed was the DPRK's nuclear and missile threats.