North Korean leader Kim Jong Un threatens more nuclear weapons amid US 'hostility'

North Korean leader Kim Jong Un visits a cosmetics factory in Pyongyang on October 29, 2018. Photo / KCNA

North Korean leader Kim Jong Un has threatened to expand his nuclear arsenal, saying the fate of relations with the United States depends on whether it abandons its "hostile policy".

Kim's comments made today during a key ruling party meeting were seen as an effort to apply pressure on the incoming government of US President-elect Joe Biden, who is to take office on January 20.

The state-run Korean Central News Agency (KNCA) reported 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" on North Korea.

Kim says he won't use his nukes unless "hostile forces" intend to use their nuclear weapons against North Korea first.

But he says North Korea must further strengthen its military and nuclear capability as the danger of a US invasion on North Korea increases.

US President-elect Joe Biden. Photo / AP

Kim ordered officials to develop missiles with multiple warheads, underwater-launched nuclear missiles, spy satellites and nuclear-powered submarines.

The KCNA says Kim's order was made during a fourth-day meeting of his country's first ruling party congress in five years.