North Korea's ruling party newspaper says the country's military held large-scale military exercises with leader Kim Jong Un attending.

The Rodong Sinmun reported on Monday that "long-range artillery sub-units on the front and flying corps" conducted the drills on Thursday and Saturday.

The paper says North Korean forces on Thursday attacked an islet standing in for an enemy military base with "air-to-surface medium-range guided bombs and cruise missiles" and "bombing flights."

Saturday's drill was held after the USS nuclear-powered aircraft carrier Ronald Reagan was deployed again in the Sea of Japan.

The paper says the air force "carried out a large-scale combined air-attack drill during which more than 150 fighter planes of different missions took off simultaneously for the first time in history."

It says the aim was "to reconfirm the scale, procedure, ways and tactics of air strikes against various operational targets." The paper added that "through the test-firing of new-type air weapon systems, their reliability was proved."

North Korean forces also took part in a nighttime drill to "strike a target assumed to be the enemy's operational airfield."

The Rodong Sinmun carried photos of Kim watching an artillery shell hitting a target and fighter jets flying in formation and carrying out air strikes.

It quoted Kim as saying that "in the steadily-deteriorating military situation" around North Korea, "more rapid and proper preparedness for war and the improved military counteraction ability" is essential.