Several of the missiles were displayed at a parade overseen by leader Kim Jong-un, reported state media.
Members of the WPK's central leadership body and the military's commanding officials appeared at the tribune, according to the report.
Soldiers march in Thursday's military parade.
The weapons systems displayed as a whole were less impressive than those trotted out in October, when North Korea celebrated the 75th anniversary of the foundation of the Workers' Party of Korea, the Communist organ that rules the country.
This picture released from North Korea's official Korean Central News Agency (KCNA) shows what appears to be submarine-launched ballistic missiles during a military parade celebrating the 8th Congress of the Workers' Party of Korea (WPK) in Pyongyang, January 14, 2021. Speaking at the congress, Kim said that no matter who is president, the U.S. will remain North Korea's "biggest enemy", arguing that "the true nature of the USA and its fundamental policies" towards Pyongyang "will never change".
A working SLBM on a nuclear-powered submarine would be a strategic game-changer, enabling Pyongyang to launch a surprise attack from close to the United States or carry out a strike even if its land-based forces had been destroyed. Each new missile helps bolster his argument that the US should drop its demands for "final, fully verified denuclearization" and accept North Korea as a nuclear-armed state.
Although the display did not feature North Korea's dreaded ICBMs (intercontinental ballistic missiles) - capable of hitting the USA mainland - it showcased what experts estimated were upgraded versions of short-range ballistic missiles (SRBMs) and submarine-launched ballistic missiles (SLBMs).
The display comes just days after Kim said North Korea was pursuing sophisticated new armaments for the country's nuclear weapons and ballistic missile programs, including a nuclear-powered submarine, tactical nuclear weapons and advanced warheads created to penetrate missile defense systems.
It said the missiles "powerfully demonstrate the might of the revolutionary armed forces".
"These parades aren't just for the outside world, of course", said Panda, author of "Kim Jong Un and the Bomb: Survival and Deterrence in North Korea".
North Korea tested the Pukguksong-3, which flew about 450 kilometers and reached a maximum altitude of 910 km, in October 2019. North Korean state TV hasn't released footage of the event, and the South Korean and USA militaries haven't yet provided assessments of the weapons displayed by the North. But it wasn't immediately clear whether the description was referring to intercontinental ballistic missiles. Defense Minister Kim Jong-gwan delivered a speech, according to state media.
In the end, a number of what analysts said appeared to be new variants of short-range ballistic missiles and SLBMs rolled into the square on trucks. This is a show of strength - flexing the military muscle once more to show the people of North Korea that despite the current bleak economic outlook, this impoverished country is capable of designing and building new strategic weapons.
Images showed the display culminating with what appeared to be a new solid-fuel short-range ballistic missile, which are more mobile and more quickly deployed than liquid-fuelled versions. "Despite or perhaps because of this, Kim Jong Un feels the need to devote scarce resources to another political-military display". While the country is believed to have accumulated at least dozens of nuclear weapons, outside estimates on the exact status of its nuclear and missiles programmes vary widely.
North Korea claims to not have recorded a single case of Covid-19, so holding a major event without masks may be a way to reinforce that narrative. The parade appeared to echo messages trumpeted at the gathering - that Pyongyang would not back down from US efforts to throttle it into submission, and that it would further modernize its nuclear arms as a means to ensure its survival.
After the previous congress in 2016, the first in 36 years, Kim accelerated the development of nuclear weapons and ICBMs, which could become a direct threat to the United States.
