Kim also inspected factories producing shells for super large-calibre multiple rocket launchers and transporter-erector-launchers, which are normally used to fire ballistic missiles, KCNA reported.

He gave instructions for increasing production capacities at the factories as an important part of bolstering the country's defence capabilities, KCNA said.

Inspecting the munitions factory, Kim noted improved precision processing and modernized automation in the production of large-calibre multiple rocket launcher shells, KCNA said.

North Korea has tested rocket launchers for larger calibre shells, advanced cruise missiles and, last month, its newest ballistic missiles including solid-fuel intercontinental ballistic missile (ICBM).

Kim called for the mass-production of "various kinds of cutting-edge strategic weapon engines ... and thus make a great contribution to bringing about a revolution in developing new strategic weapons of our style," KCNA said.

Kim's reported visits to multiple arms production facilities over several consecutive days were unusual but come amid a push by the country to develop various strategic and conventional weapons and recent prominent displays of a range of weapons.

In late July, marking the 70th anniversary of the end of the Korean War, it put on a major military parade displaying its newest nuclear-capable missiles and attack and spy drones with senior officials from Beijing and Moscow in attendance, including Russia's Defence Minister Sergei Shoigu.

North Korea also held a large defence exhibition to coincide with the anniversary and Kim gave Shoigu a tour of the display of ballistic missiles and what appeared to be a new drone.

The United States has accused North Korea of providing arms to Russia for its war with Ukraine, including a "significant" number of artillery shells, as well as a shipment of infantry rockets and missiles to the private Russian military company, the Wagner Group.

Both Russia and North Korea have denied those claims.