The Ninth Congress of the Workers' Party of Korea "opened with great ceremony in Pyongyang" on Thursday, the Korean Central News Agency said.

The congress is the ruling party's top gathering, a grand political set-piece that reinforces the regime's authority and can serve as a platform for announcements of policy shifts or elite personnel changes.

Since the 2021 event, North Korea has continued to develop its nuclear arsenal, repeatedly test-launching intercontinental ballistic missiles in defiance of bans ordered by the UN Security Council.

Pyongyang has also developed deep ties with Moscow during its war in Ukraine, with North Korean soldiers sent to fight alongside Russian forces.

In 2024, the two countries signed a treaty including a mutual defence clause.

Pyongyang's leader Kim Jong Un touted a newly built street of flats for families of soldiers killed supporting Russia's war against Ukraine, state media reported Monday.

Observers have been scouring satellite imagery for any signs of the vast military parades that have marked previous gatherings.

Any parade will be closely watched for signs of a shift in North Korea's military bearing.

Pyongyang has used previous processions to show off its newest and most potent weapons, a rare source of insight into the strength of its armed forces.

- Biggest enemy -

At the previous congress five years ago, Kim declared that the United States was his nation's "biggest enemy".

There is keen interest in whether he might soften this stance, or double down.

US President Donald Trump stepped up his courtship of Kim during a tour of Asia last year, saying he was "100 percent" open to a meeting.

He even bucked decades of US policy by conceding that North Korea was "sort of a nuclear power".

But Kim has so far refused to take the bait.

Kim appeared alongside China's Xi Jinping and Russia's Vladimir Putin at a grand military parade in Beijing last year -- a striking display of his powerful friends and elevated status in global politics.

North Korea's economy has for years languished under heavy Western sanctions on everything from oil to seafood, measures that aim to choke off funding for its nuclear weapons programme.

Late last month, Kim oversaw the test launch of missiles from a multiple rocket launcher and said that "next-stage plans for further bolstering up the country's nuclear war deterrent" would be clarified at the upcoming party congress.

Kim was accompanied at the test by his daughter Ju Ae, believed to be his likely successor.

Close attention will be paid to whether Ju Ae will be given any official party titles at this year's congress.