N Korea displays ICBMs at huge parade, vows to boost nuclear arsenal

North Korea will speed up development of its nuclear arsenal, leader Kim Jong Un said while overseeing a huge military parade that displayed intercontinental ballistic missiles (ICBMs) and other weapons, state media reported on Tuesday.

The parade occurred Monday night during celebrations for the founding anniversary of North Korea's armed forces, state news agency KCNA said. It comes as Pyongyang has stepped up weapons tests and displays of military power amid stalled denuclearisation talks with the United States and an incoming conservative administration in South Korea.

US and South Korean officials say there are signs of new construction at North Korea's only known nuclear test site, which has been officially shuttered since 2018, suggesting Pyongyang may be preparing to resume testing nuclear weapons.

"The nuclear force of the Republic must be ready to exercise its responsible mission and unique deterrence anytime," Kim told the gathering, according to KCNA.

The fundamental mission of the North's nuclear force is to deter war, but that may not be the only use, he added.

"If any force seeks to intrude on the fundamental interests of our nation, our nuclear forces will be forced to unexpectedly carry out their second mission," Kim said.

The parade featured North Korea's largest known ICBM, the Hwasong-17, KCNA reported. The massive missile was test fired for the first time last month, but officials in South Korea believe efforts to conduct a full test ended in an explosion over Pyongyang.

North Korea's Rodong Sinmun newspaper released photos showing the Hwasong-17, as well as what appeared to be hypersonic missiles and submarine-launched ballistic missiles (SLBMs), among other weapons on trucks and launching vehicles rolling by crowds of flag-waving observers and participants.

The procession also included rows of conventional weapons such as artillery, rocket launchers, andprototype tanks, plus tens of thousands of goose-stepping troops shouting "long life" to Kim Jong Un.

North Korea's ballistic missile and nuclear weapons programmes are banned by United Nations Security Council resolutions, which have imposed sanctions on the country.

In the latest weapons test on 16 April, Kim oversaw the launch of what state media said were short-range missiles that could deliver tactical nuclear weapons.

During a visit to Seoul last week, Sung Kim, the US envoy on North Korea said the allies would "respond responsibly and decisively to provocative behaviour," while underlining his willingness to engage with North Korea "anywhere without any conditions."

North Korea has said it is open to diplomacy, but has rejected Washington's overtures as insincere in view of what Pyongyang sees as "hostile policies" such as sanctions and military drills with the South.