SEOUL, SOUTH KOREA — As North Korea's leader, Kim Jong Un, convened a party congress over the past eight days, outside analysts wondered whether his failure to improve the economic lives of his people would affect the dictator's nuclear ambitions.

At the gathering of his ruling Workers' Party, Kim provided an unequivocal answer: absolutely not.

Establishing a nuclear force, Kim said, has been "a strategic and predominant goal​" and "the exploit of greatest significance in the history of the Korean nation." In a resolution adopted Tuesday, laying out the party's plans for the next five years, he vowed to "further strengthen our nuclear deterrence."

During the party meeting, the first of its kind since 2016, Kim doubled down on his nuclear arms buildup, offering an unusually detailed list of weapons that the North was developing. They included "ultramodern tactical nuclear weapons," "hypersonic gliding-flight warheads," "multi-warhead" missiles, military reconnaissance satellites, a nuclear-powered submarine, and land- and submarine-launched intercontinental ballistic missiles that use solid fuel.

The country's economy has been ravaged by the pandemic, extensive flood damage and years of international sanctions. Kim acknowledged that his economic plans had failed, but he said he did not see his nuclear weapons program as an obstacle toward rebuilding the economy.

Rather, he saw it as the best tool he had to ensure the continuity of his dynasty and extract economic and other concessions from the U.S., which he called "our foremost principal enemy​" during the party meeting.

As President Donald Trump's term comes to a close, he is leaving behind a North Korea with a nuclear program that is more ambitious than ever, after touting his on-and-off diplomacy and "personal relationship" with Kim.

"It's nuclear intimidation, nuclear blackmailing," said Tae Yong-ho, a former North Korean diplomat in London who defected to South Korea, where he is now a lawmaker.

Kim appears willing to negotiate with President-elect Joe Biden's incoming administration, but unlikely to seek talks on scrapping his nuclear weapons program. It is more likely that he will propose the kind of nuclear arms control negotiations the U.S. had with the former Soviet Union.​

In his lengthy policy review to the congress over the weekend, Kim called North Korea "a responsible nuclear weapons state" that would not use its arsenal unless it was first threatened with a nuclear weapon. Kim said he "never precludes diplomacy" but would use his growing nuclear force as powerful leverage.

Kim said his goal in negotiating with Washington was a "withdrawal of its hostile policy," including an end to sanctions and to joint military exercises with South Korea, as well as other alliance activities around the Korean Peninsula. But Seoul and Washington say their military exercises are compelled by the North's growing nuclear and missile threat.

"The North will continue its hard-line policy, will not denuclearize, will talk to the U.S. but on what Kim Jong Un perceives as an equal footing as a nuclear power," said David Maxwell, a senior fellow at the Washington-based Foundation for Defense of Democracies.

It's unclear whether and how fast North Korea can achieve Kim's arms buildup goals. But his raising of the stakes reflects the hard realities he faces as the country's supreme leader.

Under Kim, North Korea has conducted four of its six underground nuclear tests and flight-tested three intercontinental ballistic missiles. After the last of those missile tests, in 2017, Kim said North Korea was now capable of targeting the continental U.S. with nuclear missiles.