A meeting of the party Central Committee's politburo "gave an instruction to a sector concerned... to promptly examine the issue of restarting" all activities that had been temporarily suspended, state media KCNA reported, in a likely reference to Pyongyang's nuclear and ICBM (intercontinental ballistic missile) programs.

"The hostile policy and military threat by the US have reached a danger line that can not be overlooked any more," KCNA said.

Kim, North Korea's reclusive leader, presided over the politburo meeting which was presented a report analysing conditions on the Korean peninsula and addressing "the orientation for countermeasures against the US for the future."

The North Korean leader declared a self-imposed moratorium on nuclear and inter-continental ballistic missile (ICBM) tests in 2018, but threatened to lift it after talks with then-president Donald Trump collapsed in 2019.

The country has conducted a flurry of sanctions-busting launches this year, including hypersonic missiles, as it flexes its military muscles while rebuffing Washington's offers of talks.

Kim reavowed his commitment to military modernisation at a key party speech last month, while not mentioning the United States.

Washington hit Pyongyang with fresh sanctions last week, and North Korea responded by doubling down on testing, asserting its "legitimate right" to self-defence.

North Korea has also ramped up its anti-Washington rhetoric.

"The US viciously slurred our state and committed the foolish act of taking over 20 independent sanctions measures," according to KCNA.

The agency said the politburo unanimously agreed that North Korea should "make more thorough preparation for a long-term confrontation with the U.S. imperialists," as well as "increase our physical strength for defending" the rights and interests of the nation.