North Korea's ruling Workers' Party newspaper, Rodong Sinmun, wrote in its Monday edition that the country's leader Kim Jong Un oversaw military drills of tactical nuclear operations units.

The drills took place between September 25 and October 9.

It was the first time that Pyongyang mentioned the drills of the tactical nuclear operations units.

The paper says that the drills took place as a warning after the United States deployed the nuclear-powered aircraft carrier Ronald Reagan during a joint exercise with South Korea and Japan in the Sea of Japan.

It says that seven launches of missiles showed the full extent of the country's nuclear combat forces' war capabilities.

The paper reported on the ballistic missile launch on October 4 saying that it hit the targeted water area in the Pacific, 4,500 kilometers away, after flying over Japan. It says it was a new type of ground-to-ground intermediate range ballistic missile.

It said that in order to cope with the unstable situation on the Korean Peninsula, the Central Military Commission of the Workers' Party decided to send a more powerful and clear warning to enemies.

The newspaper carried about 90 photographs of the drills. Some of them show Kim watching a monitor indicating a trajectory of the missile going over Japan.

It reported that Kim said that military moves of the enemies are strictly watched and that all military countermeasures will be taken if necessary.

The ruling party marks its 77th anniversary on Monday and observers are keenly watching to see if a celebration takes place with Kim presence.