North Korea's leader Kim Jong Un addresses a special workshop for officials in the party life guidance sections of organisational departments of party committees at all levels of the Workers' Party of Korea (WPK) in Pyongyang, North Korea, in this undated
North Korea's leader Kim Jong Un addresses a special workshop for officials in the party life guidance sections of organisational departments of party committees at all levels of the Workers' Party of Korea (WPK) in Pyongyang, North Korea, in this undated photo released by North Korea's Korean Central News Agency (KCNA) July 7, 2022. Reuters / KCNA

North Korean leader Kim Jong Un said his country is ready to mobilise its nuclear war deterrent and for any military clash with the United States, state media reported on Thursday, amid signs the North could conduct its first nuclear test since 2017.

Kim made the remarks during a speech at an event to mark the 69th anniversary of the July 27 Korean War armistice, which left the two Koreas technically still at war, according to the official KCNA news agency.

The confrontation with the United States posed nuclear threats since the conflict required the North to achieve an "urgent historical task" of beefing up its self defence, Kim said.

"Our armed forces are thoroughly prepared to respond to any crisis, and our nation's nuclear war deterrence is also fully ready to mobilise its absolute strength faithfully, accurately and promptly to its mission," he said.

The speech came after Seoul and Washington officials said Pyongyang has completed preparations to conduct its first nuclear test since 2017.

South Korea's unification minister handling inter-Korean affairs said on Tuesday there was a "possibility" of the test in time for the anniversary, though a military official said there were no immediate signs for it.

North Korea is likely to face stronger sanctions including measures aimed at curbing its cyberattack capabilities if it goes ahead with the test, South Korea's foreign minister said on Wednesday.

In the speech, Kim said Washington continues "dangerous, illegal hostile acts" with South Korea against the North some 70 years after the war, and seeks to justify its behaviour by "demonising" the country.

The North has long accused the United States of double standards over military activities and pursuing a hostile policy towards Pyongyang, saying it hampers a restart of talks aimed at dismantling the country's nuclear and missile programmes in return for sanctions relief.

"The duplex act of the United States, which is misleading all the routine actions of our armed forces as 'provocation' and 'threat' while holding large-scale joint military exercises that seriously threaten our security, is literally a robbery," Kim said.

"That is driving bilateral relations to the point where it is difficult to turn back, into a state of conflict."

Kim denounced South Korea's Yoon Suk-yeol administration, saying any attempts to preemptively incapacitate the North would be met with a stern response and "annihilation".

"I once again make it clear that North Korea is fully ready for any military confrontation with the United States," Kim said.

North Korea in recent months has tested hypersonic missiles and missiles that it says could carry tactical nuclear weapons, narrowing the time that Seoul would have to respond to a pending attack.