Seoul, Jul 20 (IANS): South Korean and US military intelligence agencies have detected an unusual level of activity involving North Korean submarines in regional waters, a Defence Ministry spokesperson confirmed here on Thursday.

The official told Efe news that the agencies are currently working to gather more information about the nature of the activities.

The information comes after Pentagon officials informed the US Senate earlier this week that the Kim Jong-un regime is conducting tests of components for another submarine-launched ballistic missile test (SLBM).

North Korea conducted its first successful SLBM test in August 2016, when it launched the Pukkuksong-1 missile in waters near Sinpo, its main submarine missile base.

The Pyongyang regime carried out its latest ballistic missile test on July 4, when it fired for the first time an intercontinental ballistic missile, believed to be capable of reaching Alaska.

North Korea's submarine fleet is believed to encompass around 70 subs, though the majority are quite old and likely cannot fire missiles, reports CNN.