Kim Jong Un vowed to beef up North Korea's defence capabilities, citing military modernisation efforts by South Korea and the United States pushing the region "to the brink of a nuclear war", state media reported Tuesday.

Pyongyang is under multiple sets of sanctions over its nuclear programme, and the two Koreas remain technically at war because their 1950-53 conflict ended in an armistice rather than a peace treaty.

"Comrade Kim Jong Un in his concluding speech reaffirmed the steadfast policy stand of our Party and state to beef up the national defence capabilities faster," the official Korean Central News Agency quoted the leader as saying.

The speech was delivered as Kim presided over a three-day meeting of the Workers' Party of Korea that wrapped up on Monday, during which senior officials reviewed policy initiatives, KCNA said.

It quoted Kim as saying "the US and the ROK are pushing forward with the ROK's possession of a nuclear submarine while getting evermore undisguised in their moves towards the reinforcement and modernisation of armed forces in the region", referring to South Korea by the acronym of its official name.

According to KCNA, Kim said such moves were "pushing the situation in the Korean peninsula to the brink of a nuclear war".

In the face of such developments, it was the "steadfast stand" of the North to "further expand and strengthen the powerful and absolutely reliable deterrent for self-defence", Kim said.

'Line of no retreat'
KCNA said the meeting "unanimously recognised that to steadily expand and strengthen the nuclear forces... is the most correct and unique way to actively and confidently cope with the unpredictable international military and political situation".

It added the North's development of a war deterrent "with nuclear technology as a basis" would proceed "at increasing speed".

Pyongyang has repeatedly declared itself an "irreversible" nuclear state since a 2019 summit between Kim and Trump in Hanoi collapsed over the scope of denuclearisation and sanctions relief.

Kim's powerful sister, Yo Jong, said this month the North's nuclear policy was a "line of no retreat", reiterating the regime's position that it has no intention of giving up its nuclear arsenal.

South Korean President Lee Jae Myung said last week that US counterpart Donald Trump had told him it was time to "pay attention to the North Korea issue".

He told reporters he had told Trump at a meeting of the G7 in France that sanctions on the North were "ineffective."

"I also said that we can no longer deal with the North Korean nuclear issue in the same way we deal with other countries, and President Trump agreed," Lee added.