UNITED NATIONS -- The U.S. will maintain "maximum pressure" on North Korea until the country takes concrete steps toward dismantling its nuclear weapons program, President Donald Trump's national security adviser, H.R. McMaster, told reporters Monday.
"We're determined to keep up the campaign of maximum pressure until we see words matched with deeds and real progress towards denuclearization," McMaster said after briefing members of the U.N. Security Council about U.S. diplomatic initiatives with the communist country.
The briefing followed a White House announcement on Thursday that Trump has accepted an invitation to meet Kim Jong Un in what would be the first-ever direct talks between a U.S. president and a North Korean leader.
The apparent diplomatic thaw follows several rounds of nuclear and ballistic missile tests by North Korea last year that have isolated country on the verge of being able to strike the U.S. mainland with nuclear-tipped missiles. That prompted a rapid ratcheting up of U.N. economic sanctions against North Korea.
McMaster voiced guarded optimism about the prospects for a diplomatic solution to the nuclear standoff.
"We all agreed that we're optimistic about this opportunity," McMaster said after the closed-door, 90-minute session at the U.S. mission to the U.N. McMaster said he communicated to the council "our common intention to keep up the campaign of maximum pressure."
Nikki Haley, Washington's U.N. ambassador, also stressed the need to stay the course. "Three resolutions were passed in the U.N. unanimously by the Security Council that cut off all exports, 90% of trade, 30% of oil, disbanded their labor pool," Haley told reporters. "All of those things led to the pressure that amounted to this."
South Korea's representative to the U.N. supported her comments. "Many of my colleagues agree" on the approach taken by the Trump administration, Cho Tae-yul told reporters. But he also called on the council to take advantage of the opportunity for negotiations.
"I emphasized this is also a once in a lifetime opportunity for a peaceful resolution on the issue, so we have to keep up the momentum on that," Cho said.
Nikkei staff writer Ariana King contributed to this report.