Kim Jong-un has said he is planning a “new strategic weapon” in a New Year address that saw him rail against the US and Donald Trump.

North Korea would continue developing “necessary” strategic weapons until the US drops its hostile policy towards the country, Mr Kim said in the highly-anticipated address to the key ruling Workers’ Party meeting.

He said the country was working on a new nuclear deterrent but that the scale of it would depend on the two countries’ future relationship, according to a report from state media organisation KCNA.

And he threatened that the US would “suffer helplessly” if there continued to be delays in talks aimed at dismantling North Korea‘s nuclear and missile programmes.

Mr Kim accused the Trump administration of having “gangster-like demands” but did not explicitly rule out further talks between the two countries.

Kim Jong-un: Power in pictures Show all 20 1 /20 Kim Jong-un: Power in pictures Kim Jong-un: Power in pictures Kim Jong-un rides a horse during snowfall in Mount Paektu in this image released by North Korea's Korean Central News Agency on 16 October 2019 Reuters Kim Jong-un: Power in pictures Kim Jong-un visits the newly built Pyongyang Orphans' Primary School on 2 February 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects a women's company under Unit 5492 of the Korean People's Army in November 2019 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects the test-fire of intercontinental ballistic missile Hwasong-14 at an undisclosed location in July 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un celebrates the successful test-fire of the intercontinental ballistic missile Hwasong-14 at an undisclosed location in July 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects a potato at the Samjiyon Potato Factory in North Korea in October 2018 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un rides a horse through a forest in this image released by North Korea's Korean Central News Agency on 16 October 2019 EPA Kim Jong-un: Power in pictures Kim Jong-un inspects a block of frozen fish at a processing facility in North Korea in November 2018 Reuters Kim Jong-un: Power in pictures Kim Jong-un celebrates the succeful launch of a strategic submarine-launched ballistic missile in August 2016 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un shakes hands with Donald Trump as they meet for the first time at the Capella Hotel on Sentosa island in Singapore in June 2018 Reuters Kim Jong-un: Power in pictures Kim Jong-un and Donald Trump share a glance as they meet in the Demilitarised Zone in Panmunjon, Korea in June 2019 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects mushrooms at Pyongyang Mushroom Farm AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects a super-large multiple rocket launcher ahead of a test in September 2019 Reuters Kim Jong-un: Power in pictures Kim Jong-un inspects an apple farm in South Hwanghae Province in September 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects an apple farm in South Hwanghae Province in September 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects dental wares at a newly built factory in June 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un visits Farm No 1116 in September 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un visits a motor factory in November 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un rides a horse during snowfall in Mount Paektu in this image released by North Korea's Korean Central News Agency on 16 October 2019 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects the Command of the Strategic Force of the Korean People's Army at an undisclosed location in August 2017 AFP/Getty

In an interview with Fox News, US secretary of state Mike Pompeo said that he hoped Mr Kim "doesn't go in that direction".

"It remains the case that we hope Chairman Kim will take a different course," he said. "Hopefully he’ll choose peace and prosperity over conflict and war."

Mr Kim did not say explicitly what the threatened strategic weapon was, or how it would be demonstrated to the world. Numerous experts have expressed concern that souring relationships between the US and North Korea could see the dictator give the go-ahead to the testing of an intercontinental ballistic missile (ICBM) capable of transporting a nuclear warhead.

North Korea’s state media said Wednesday that Mr Kim had declared during a key political conference that the North will not give up its security for economic benefits and will never denuclearize unless the US discards its “hostile policy.”

Mr Kim’s comments came after a months-long standoff with Washington over exchanging sanctions relief and disarmament measures, which dimmed hopes for denuclearising the North through diplomacy.

“He said that we will never allow the impudent US to abuse the DPRK-US dialogue for meeting its sordid aim but will shift to a shocking actual action to make it pay for the pains sustained by our people so far and for the development so far restrained,” the Korean Central News Agency said, referring to the North by its formal name, the Democratic People’s Republic of Korea.

Mr Kim added that “if the US persists in its hostile policy toward the DPRK, there will never be the denuclearisation on the Korean Peninsula and the DPRK will steadily develop necessary and prerequisite strategic weapons for the security of the state until the US rolls back its hostile policy”, according to the agency.

However, Mr Kim showed no clear indication of abandoning negotiations with Washington entirely or lifting a self-imposed moratorium on tests of nuclear bombs and intercontinental ballistic missiles.

Some experts say North Korea, which has always been sensitive about electoral changes in US government, will avoid engaging in serious negotiations for a deal with Washington in coming months as it watches how Mr Trump’s impending impeachment trial over his dealings with Ukraine affects US presidential elections in November.

Mr Kim and Mr Trump have met three times since June 2018, but negotiations have faltered since the collapse of their second summit last February in Vietnam.

Mr Kim’s speech followed months of intensified testing activity and belligerent statements issued by various North Korean officials, raising concerns that he was reverting to confrontation and preparing to do something provocative if Washington did not back down and relieve sanctions.

The North announced in December that it had performed two “crucial” tests at its long-range rocket launch site that would further strengthen its nuclear deterrent, prompting speculation that it was developing an ICBM or planning a satellite launch that would provide an opportunity to advance its missile technologies.

North Korea also last year ended a 17-month pause in ballistic activity by testing a slew of solid-fuel weapons that potentially expanded its capabilities to strike targets in South Korea and Japan, including US military bases there. It also threatened to lift a self-imposed moratorium on the testing of nuclear bombs and ICBMs.