The U.S. said Monday it has yet to hear back from North Korea in the days since President Donald Trump agreed to meet in person with Pyongyang's reclusive leader, Kim Jong Un.
Secretary of State Rex Tillerson, on a visit to Nigeria, said the U.S. expects to "hear something directly" from North Korea. But he seemed unconcerned that there has been no immediate public response to Trump's acceptance of Kim's invitation for a face-to-face meeting over possible denuclearization of the Korean peninsula and other issues.
"As you know, it's a very recent development," Tillerson said. "There will be several steps ... necessary to agree on location, agree on the scope of those discussions. It's very early stages. So, I know those are all questions that people are anxious to have answers to. I would say just remain patient, and we'll see what happens."
He declined to float ideas for where the summit might occur, saying, "I think it's going to be very important that those kinds of conversations are held quietly through the two parties."
Separately, U.S. lawmakers stressed the need for exhaustive preparations and consultations involving U.S. and North Korean officials ahead of a Trump-Kim encounter.
"A lot of work needs to be done, and we ought to know how the meeting is likely to conclude before the leaders meet," Republican Senator Roy Blunt of Missouri told VOA.
"A meeting like that is not useful and, in fact, could be counterproductive unless proper preparation is done, which would involve a series of meetings by diplomats," Arizona Republican Senator Jeff Flake said.
Flake noted that extensive high-level consultations between Washington and Havana preceded former President Barack Obama's 2016 trip to Cuba.
"For months and months and months, [former U.S. Assistant Secretary of State] Roberta Jacobson was down there [in Havana] negotiating," Flake told VOA. "There is so much to take into account [regarding North Korea] — our alliances, our nonproliferation regime, things that the president [Trump] doesn't have experience with and, in my view, doesn't fully appreciate, given the statements he's made."
U.S. officials vowed Sunday they would not make any concessions to North Korea ahead of the summit and would continue to pressure North Korea.
"Make no mistake about it, while these negotiations are going on, there will be no concessions made," Central Intelligence Agency director Mike Pompeo told Fox News Sunday.
Pompeo said the North Korean ruler must "continue to allow us to perform our military-necessary exercises" with South Korea, "and then he's got to make sure that he leaves on the table that discussion for denuclearization" of his military.
Tufts University Korean Studies assistant professor Sung Yoon Lee told VOA that Kim has tricked the world into believing he has offered concessions.
"We know that nuclear and ballistic missile tests are prohibited under more than 10 U.N. Security Council resolutions, so the mere utterance of abstinence from illicit, forbidden activities is no concession at all," he said.
In the past, Trump has derided the possibility of direct talks with North Korea, telling Tillerson in October he was "wasting his time" considering the possibility of negotiations.
But on Saturday, Trump noted the historical significance of him accepting the North Korean leader's offer to meet.
"Well, they say, 'Well, [former President Barack] Obama could have done that.' Trust me, he wouldn't have done it. By the way, neither would [former President George W.] Bush or [former President Bill] Clinton," Trump said. "Anybody could have done it. Obama could have done it. Obama had his chance."
Senator Elizabeth Warren of Massachusetts, a Democratic opponent of Trump, said on NBC, "I want to see our president succeed, because if he succeeds, America succeeds. The world is safer. But I am very worried that they're going to take advantage of him."
Republican Flake recalled his own similar response years ago: "When President Obama said he was going to meet with Castro, I said, 'Good.' I'm all in favor of these kinds of meetings," he said. "What I hope is that the prep work is done."
VOA's Michael Bowman and Victor Beattie contributed to this report.