The meeting was Kim's first reported public appearance in more than three weeks and came after US media said Friday that the Trump administration had discussed holding the first US nuclear test in decades.

Set forth at the meeting of the Central Military Commission were "new policies for further increasing the nuclear war deterrence of the country," the North's official KCNA news agency said, without giving further details.

"Crucial measures" were taken "for considerably increasing the firepower strike ability of the artillery pieces of the Korean People's Army", it added.

Discussions also centred on "putting the strategic armed forces on a high alert operation", in line with the "building and development of the armed forces of the country".

The date of the meeting was not given, but a separate KCNA dispatch from the same meeting reported a military order signed by Kim was issued on May 23.

That marked Kim's first reported public appearance in more than 20 days, after he reappeared following an earlier three-week absence which triggered intense speculation about his health.

A photo carried by the official Rodong Sinmun newspaper on Sunday showed Kim wielding a long stick and pointing to what appeared to be a blurred out TV screen while making a presentation to a room full of uniformed officers.

None of those shown in the photo -- including Kim -- were wearing masks and sitting close to each other, despite the global coronavirus pandemic.

The North has insisted that it has not seen a single case of coronavirus, although experts say that is unlikely.

The meeting also reviewed and analysed "a series of drawbacks in the military and political activities" and discussed ways for "drastic improvement", according to KCNA.

- 'Nuclear testing' -

Rumours swirled for weeks about Kim's health after he failed to appear at the April 15 celebrations for the birthday of his grandfather, the North's founder -- the most important day in the country's political calendar.

His disappearance triggered a series of unconfirmed reports and fevered speculation until he reappeared at a factory opening in May.

News of the nuclear discussions came after a report Friday in The Washington Post said that the Trump administration had discussed holding the first US nuclear test since 1992 as a potential warning to Russia and China.

Daryl Kimball, executive director of the US-based Arms Control Association, told the paper that such a decision would likely "disrupt" negotiations with Kim, "who may no longer feel compelled to honour his moratorium on nuclear testing".

Negotiations between Pyongyang and Washington over the North's nuclear arsenal remain at a standstill despite three high-profile meetings between Kim and US President Donald Trump.

Pyongyang has carried out a series of weapons tests in recent months -- often describing them as multiple launch rocket systems, although Japan and the US have called them ballistic missiles.

The North is subject to multiple UN Security Council sanctions over its banned weapons programmes.