SEOUL, South Korea–North Korean leader Kim Jong Un has dismissed his top general and called for stepping up war preparations "in an offensive way", including boosting weapons production and conducting more drills, state media reported Thursday.

The developments came at a meeting of the Central Military Commission on Wednesday, the Korean Central News Agency reported, just days after Kim inspected several major arms factories.

The military gathering comes as Seoul and Washington prepare for major joint drills later this month, which the North views as rehearsals for invasion and has repeatedly warned could trigger "overwhelming" action in response.

At the meeting, Kim dismissed chief of the general staff Pak Su Il, replacing him with Vice Marshal Ri Yong Gil, KCNA said without giving further details.

KCNA said the agenda of Wednesday's meeting was "the issue of making full war preparations" including "securing more powerful strike means" to ensure "perfect military readiness for a war".

Kim called for "all the munitions industrial establishments to push ahead with the mass-production of various weapons and equipment", the report said.

"He also called for actively conducting actual war drills to efficiently operate (the) newly deployed latest weapons and equipment," it added.

Kim reached an "important conclusion on further stepping up the war preparations of the KPA in an offensive way," KCNA reported.

The meeting also discussed preparations for a massive parade to mark the 75th anniversary of the founding of North Korea on September 9.

Last month, Pyongyang held a major military parade to mark the 70th anniversary of the Korean War armistice, with analysts describing the event as "the largest, most overt North Korean display of nuclear-capable systems".

North Korea also held a large defence expo to coincide with the parade, with Kim giving the visiting Russian defence minister a tour of of the country's newest and most advanced weaponry, including ballistic missiles and spy drones.