The South Korean military has assessed that North Korea's newly unveiled tactical nuclear attack submarine is not currently capable of normal operations.

An official from the Joint Chiefs of Staff(JCS) said on Friday that they have been tracking activity related to the North's submarine launch using Seoul and Washington's combined surveillance assets.

The official said that although the North appears to have enlarged parts of the submarine's exterior, including the bridge for missile loading, it is not deemed ready for operational use. He added that it is likely the regime only unveiled the parts that do function normally.

When asked by reporters whether the latest submarine is a newly built model, the official said there is a high chance that the North modified an existing model, speculating that it could be an improved version of the three-ton Romeo-class submarine unveiled in 2019.

Earlier on Friday, the North's state media announced the launch of the Hero Kim Kun-ok tactical nuclear attack submarine, which is estimated to be capable of loading approximately ten short- to medium-range submarine-launched ballistic missiles(SLBM).