What they did not disclose then was that they believed both of those conditions had been met for an encounter already scheduled to occur.
“The vice president was ready to take this opportunity to drive home the necessity of North Korea abandoning its illicit ballistic missile and nuclear programs,” Ms. Nauert said on Tuesday.
For much of the past year, the White House has used a combination of increasingly tough economic sanctions and blistering language — including threats of military action — to try to get the North to stop, and even reverse, its missile and nuclear development programs.
United States officials have publicly insisted that they would agree to talks with Pyongyang only if North Korea agreed beforehand to give up its weapons programs, a precondition most observers believed was a nonstarter for the country.
But in the administration, a fierce debate has raged about whether to drop the preconditions, and President Moon Jae-in of South Korea is known to favor talks. About six months ago, President Trump referred to Mr. Moon’s overtures to the North as “appeasement.” Mr. Trump also dismissed Secretary of State Rex W. Tillerson’s suggestions of dialogue with the North as premature or a waste of time.
But it was never clear whether the North itself was interested in talks, preconditions or no. Under President Barack Obama, repeated efforts at opening a back channel to seek dialogue were rebuffed by Pyongyang.
Past American administrations have rewarded North Korea’s decision to begin negotiations by providing food aid and some sanctions relief. But even if there are now no preconditions for talks, the Trump administration still insists that North Korea will not be rewarded for just opening a dialogue.
“We’re not using a carrot to convince them to talk,” Mr. Tillerson said in a recent interview with “60 Minutes.” “We’re using large sticks.”
The meeting was to occur after Mr. Pence had warned that North Korea was about to face the “toughest and most aggressive” set of United States sanctions yet, though he did not detail what those would be.
Highlighting the difficulty of enforcing those sanctions, Japan on Wednesday said its military had spotted a ship-to-ship transfer of goods at sea that it “strongly suspects” violates existing United Nations sanctions on North Korea.
The transfer happened on Friday, when a Japanese surveillance plane and an escort ship spotted a North Korean-flagged tanker alongside another, smaller ship in the waters between China and Japan, Japan’s foreign ministry said. The smaller ship was of unknown nationality, though photos showed it had Chinese characters that suggested it was an oil ship from China’s Fujian Province. There appeared to be hoses connecting the two vessels.