Speculation is mounting that US President Donald Trump may seek a meeting with Kim when he travels to China later this year.

Kim made a direct appeal to the United States as a landmark congress of North Korea's ruling Workers' Party drew to a close on Wednesday evening.

If Washington "respects our country's current (nuclear) status as stipulated in the Constitution... and withdraws its hostile policy... there is no reason why we cannot get along well with the United States," Kim said, according to the Korean Central News Agency.

But Kim struck a far more combative tone when he addressed South Korea.

North Korea has "absolutely no business dealing with South Korea, its most hostile entity, and will permanently exclude South Korea from the category of compatriots", Kim said.

"As long as South Korea cannot escape the geopolitical conditions of having a border with us, the only way to live safely is to give up everything related to us and leave us alone."

North Korea's latest remarks "signal an intention to pursue relations with the US independently, without going through South Korea," Yang Moo-jin, former president of the University of North Korean Studies, told AFP.

Kim is also making clear that he will "reject any negotiations premised on denuclearisation", Yang added.

North Korea's nuclear programme has come before almost everything else in the nation for decades, even when food stocks have dried up and famine has taken hold.

High-stakes summits, crippling sanctions and prolonged diplomatic pressure have all failed to convince Pyongyang to surrender its nuclear arsenal.

Trump stepped up his courtship of Kim during a tour of Asia last year, saying he was "100 percent" open to a meeting.

He even bucked decades of US policy by conceding that North Korea was "sort of a nuclear power".

A Trump-Kim meeting would be a major breakthrough after years of deadlocked diplomacy.

- 'Grand' parade -

Their Hanoi summit in 2019 collapsed as the pair failed to come to terms on sanctions relief -- and what nuclear concessions North Korea might make in return.

Kim appeared alongside China's Xi Jinping and Russia's Vladimir Putin at a grand military parade in Beijing last year -- a striking display of his powerful friends and elevated status in global politics.

Pyongyang has particularly drawn much closer to Moscow, sending thousands of troops to aid Russia's war against Ukraine.

A "grand" military parade marked the end of the Workers' Party congress, a landmark event that directs state efforts on everything from foreign policy to war planning.

Pyongyang said a range of military units took part in the event, including troops who fought in Ukraine and those stationed near the inter-Korean border.

Held just once every five years, the days-long congress offers a rare glimpse into the workings of a nation where even mundane details are shrouded in secrecy.

"Our military will immediately launch a fierce retaliatory attack against any military hostile act committed by any force that infringes upon the sovereignty... of our country," Kim said at the parade.