In a rare military parade at night on Saturday, attended by Kim Jong-un, the nation displayed an unseen “massive” long range ballistic missile.
North Korea typically uses its parades to show off new missiles and weaponry.
The parade marked the 75th anniversary of the Workers’ Party.
It is the country’s first parade in two years and comes just weeks ahead of the US presidential election.
North Korea had not featured ballistic missiles in its parades since President Donald Trump and Mr Kim held their first summit in 2018.
According to South Korea’s military, the parade took place before dawn on Saturday. The reason for its early timing is not yet known.
No foreign media or foreigners were allowed to attend, so analysts are relying on edited state-media footage which is being released to assess the parade.
Images showed Mr Kim wearing a grey Western-style suit, receiving flowers from children.
In a speech, he said North Korea would continue to “strengthen” its military for “self-defence and deterrence”.
He also said he was grateful that no North Koreans have contracted Covid-19.
“I wish good health to all the people around the world who are fighting the ills of this evil virus,” he said.
Despite claiming the country has no cases of coronavirus, Mr Kim continues to hold high-level meetings to ensure tight restrictions remain in place.
Analysts have said it is highly unlikely that North Korea has not experienced any coronavirus cases at all.
There was no sign of anyone wearing masks during the parade. However, there were far fewer people involved in the event than usual, AFP news agency reports.
North Korea closed its borders to the outside world in January to prevent an outbreak of Covid-19 spreading from neighbouring China.
Authorities have reportedly issued “shoot-to-kill” orders along the border and created a buffer zone to stop anyone entering the country.
For weeks, satellite imagery has shown thousands of people practising for Saturday’s parade.
Foreign officials in Pyongyang had been told to avoid travelling through the city, going near the event venue and taking photos of the event.