Kim inspected one of his fleets in the East Sea, also known as the Sea of Japan, and watched as the crew staged a drill launching "strategic cruise missiles," state-run news agency KCNA reported.

It did not say when the visit took place, or give further details on the types of missiles launched -- though it said they "rapidly hit target without even an error".

The announcement came ahead of the annual Ulchi Freedom Shield drills, a major joint exercise between Seoul and Washington that will run through August 31.

They are aimed at countering growing threats from the nuclear-armed North.

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

Suspected North Korean hackers have already targeted the exercises, with email attacks on South Korean contractors working at the allies' combined exercise war simulation centre, police have said.

The announcement of the cruise missile test also comes days after US President Joe Biden hosted South Korean leader Yoon Suk Yeol -- along with Japanese Prime Minister Fumio Kishida -- at Camp David.

At a press conference on Friday the leaders said they saw a "new chapter" of close three-way security cooperation after the summit, which would have been unthinkable until recently due to the legacy of Japan's harsh 1910-1945 occupation of the Korean peninsula.

It was the first time the three countries' leaders have met for a standalone summit, and while China was a main topic, they also discussed North Korea.

The three leaders agreed to a multi-year plan of regular exercises in all domains, going beyond one-off drills in response to Pyongyang, and made a formal "commitment to consult" during crises, with Biden saying they would open a hotline.

The leaders also agreed to share real-time data on North Korea and to hold summits every year.