Kim Jong-un has threatened to expand North Korea's nuclear arsenal after revealing a list of high-tech weapons systems under development.
The North Korean leader warned the fate of relations with the US depends on whether it abandons its policy, state media in Pyongyang reported.
It comes after a meeting of key meeting aimed at applying pressure on Joe Biden's administration, who has called Kim a "thug" and criticised president Trump's summits with him.
The Korean Central News Agency quoted Kim as saying the “key to establishing new relations between (North Korea) and the United States is whether the United States withdraws its hostile policy”.
Kim said he will not use his nuclear weapons first unless threatened. He also suggested he is open to dialogue if Washington is, but stressed North Korea must further strengthen its military and nuclear capability to cope with intensifying US hostility.
He again called the US his country’s “main enemy”.
“Whoever takes office in the US, its basic nature and hostile policy will never change,” he said.
Mr Biden, who will take office on January 20, is unlikely to hold direct meetings with Kim unless the North Korean leader takes significant denuclearisation steps.
Kim did not cite any specific provocative US actions. North Korea has previously called regular US military drills with South Korea an invasion rehearsal, though the allies have repeatedly denied that.
The North Korean leader listed sophisticated weapons systems he said were under development, including a multi-warhead missile, underwater-launched nuclear missiles, solid-fuelled long-range missiles and spy satellites.
He said Pyongyang must also advance the precision attack capability on targets in 15,000-kilometre (9,320-mile) range – an apparent reference to the US mainland – and develop technology to manufacture smaller nuclear warheads to be mounted on long-range missiles more easily.
“The reality is that we can achieve peace and prosperity on the Korean peninsula when we constantly build up our national defence and suppress US military threats,” Kim said.
It is unclear if North Korea is capable of developing such systems. It is one of the world’s most cloistered countries, and estimates on the status of its nuclear and missile programmes vary widely. In 2018, the South Korean government said North Korea was estimated to have up to 60 nuclear weapons.