[PYONGYANG] Kim Jong-Un on Friday opened North Korea's first ruling party congress for nearly 40 years with a defiant defence of the "magnificent" strides made in the country's nuclear weapons programme.
Hailing the historic test of what North Korea claims was a hydrogen bomb in January, the isolated state's young leader said it had shown the world it would not be cowed by sanctions or outside pressure.
Dressed in a western style suit and tie, Mr Kim's speech was delivered to thousands of party delegates who had gathered in Pyongyang for the once-in-a-generation conclave.
In particular, he praised the country's scientists for "creating milestone miracles with the magnificent and exhilarating sound of the first H-bomb of our republic".
The test and successful long-range rocket launch a month later "clearly demonstrated to the whole world our undefeatable spirit and endless power ... in defiance of malicious pressure and sanctions by enemy forces", he said.
Most experts have questioned the North's H-bomb claim, saying the detected yield from the January test was far too low for a full-fledged thermonuclear device.
There has been widespread speculation that the North might have prepared another nuclear test to coincide with the congress, as a defiant gesture to underscore its nuclear power status.
The 33-year-old Mr Kim, who was not even born when the last Workers' Party Congress was held in 1980, said the party conclave would prove to be a "new milestone" that would lay out the future direction "of our revolutionary march".
It is still unclear how many days the congress will last, but the speeches and delegate reports will be scrutinised for any sign of a substantive policy shift, especially on the economic front.
Analysts will be watching for personnel changes as Mr Kim looks to bring in a younger generation of leaders hand-picked for their loyalty.
The state TV announcer said the congress had also discussed the operations of its powerful central military committee, revisions of party rules and elections to central party organs.
Around 130 foreign journalists had been invited to cover the event, but were not allowed inside the congress venue.
The 1980 congress was staged to crown Mr Kim's father Mr Kim Jong-Il as heir apparent to his own father, the North's founding leader Mr Kim Il-Sung.
The 2016 version was held inside the imposing April 25 Palace in Pyongyang - its stone facade adorned with huge portraits of the two late leaders, along with giant red and gold party banners.
While the agenda had been kept secret, analysts said it amounted to a formal "coronation" of Mr Kim Jong-Un as supreme leader and the legitimate inheritor of the Mr Kim family's dynastic rule which spans almost seven decades.
It was also expected to enshrine as formal party doctrine Mr Kim's "byungjin" policy of pursuing nuclear weapons in tandem with economic development.
The North Korean capital was immaculately primped and primed for the congress, with national and Workers' Party flags lining the streets, along with banners carrying slogans such as "Great comrades Mr Kim Il-Sung and Mr Kim Jong-Il will always be with us".
Preparation had involved mobilising the entire country in a 70-day campaign that New York-based Human Rights Watch denounced as a mass exercise in forced labour.
In his speech, Mr Kim described the campaign as an "extraordinary feat" that had helped the country meet its economic target for the first half of the year.
Since Mr Kim took power after the death of his father in December 2011, North Korea has carried out two nuclear tests and two successful space rocket launches that were widely seen as disguised ballistic missile tests.
Even as the international community responded with tougher sanctions, he pressed ahead with a single-minded drive for a credible nuclear deterrent with additional missile and technical tests.
He also demonstrated a ruthless streak, purging the party, government and powerful military of those seen as disloyal, and ordering the execution of his powerful uncle, and one-time political mentor, Jang Song-Thaek.