Kim expressed "satisfaction" over the weekend drills, which were held to "let relevant units get familiar with the procedures and processes for implementing their tactical nuclear attack missions", the report said.

The drills were the fourth show of force from Pyongyang in a week and came as South Korea and the United States stage their own military manoeuvres -- 11 days of joint drills known as Freedom Shield, their largest in five years.

North Korea views all such exercises as rehearsals for invasion and has repeatedly warned it would take "overwhelming" action in response.

Saturday and Sunday's drills were divided into exercises simulating the shift to a nuclear counterattack posture and a drill for "launching a tactical ballistic missile tipped with a mock nuclear warhead", KCNA said.

"The missile was tipped with a test warhead simulating a nuclear warhead," it added later, without giving further details.

Seoul's joint chiefs of staff said Sunday that the short-range ballistic missile fired by Pyongyang landed in the East Sea, also known as the Sea of Japan.

They branded it a "serious provocation" that violated United Nations sanctions and said it was being analysed by US and South Korean intelligence.

Seoul and Washington have ramped up defence cooperation in the face of growing military and nuclear threats from the North, which has conducted a series of banned weapons tests in recent months.