North Korean media say the country carried out firing drills involving what it calls "super-large rocket launchers" on Monday under the supervision of its leader Kim Jong Un.

The ruling Workers' Party newspaper Rodong Sinmun and other media said on Tuesday that the drills were aimed at strengthening the country's nuclear counterattack capabilities.

The super-large rocket is believed to be a short-range ballistic missile capable of carrying a tactical nuclear warhead.

Pyongyang insists that it can reach any part of South Korea.

The South Korean military said on Monday that the North launched what appeared to be multiple short-range ballistic missiles from a point near Pyongyang toward waters off the Korean Peninsula's eastern coast.