"We've not heard anything directly back from North Korea, although we expect to hear something directly from them," Tillerson said in Abuja, Nigeria, in response to a reporter's question about the timing and location of the meeting. "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."
Tillerson's remarks that these things take time contrast with Trump's on-the-spot acceptance of Kim's invitation when South Korea's national security adviser informed him about it at the White House last week. Trump dispensed with decades of U.S. foreign policy orthodoxy with his decision, particularly given that the North Korean leader made only a vague offer -- conveyed via a South Korean delegation that visited him -- to discuss giving up his nuclear weapons program.
The decision to meet drew support from countries seeking to defuse tensions between North Korea and the U.S., along with warnings that Kim may be playing for more time to develop his weapons while seeking relief from U.S.-led international sanctions.
Tillerson has been working the issue several time zones ahead of the U.S. East Coast during a five-nation swing through sub-Saharan Africa. Dealing with the North Korea issue is one reason he decided Monday to cut short the trip by a day and return home. Trump's announcement has raised speculation about whether the meeting will actually go ahead, what North Korea will demand from the U.S. and even where the two leaders might meet.
"Nothing's been agreed and I don't want to start floating ideas out through the media," Tillerson said in Abuja alongside Foreign Minister Geoffrey Onyeama. "I think it's going to be very important that those kind of conversations are held quietly through the two parties."
Among the unverified reports so far is that Kim hopes to sign a peace treaty with Trump - a long-held goal of the North Korean regime. Kim is likely to raise the possibility of such a treaty along with establishing diplomatic relations and moving toward nuclear disarmament, during a meeting with the U.S. leader, the Dong-A Ilbo newspaper said Monday, citing an unidentified senior official in South Korea's presidential office.
"There were agreements between the U.S. and North Korea to open up discussion on a peace treaty, but they never materialized," Koh said, saying the conditions were key. "The U.S. wants a peace treaty at the end of the denuclearization process, while for the North, it's the precondition for its denuclearization."
Signing a peace treaty would require addressing issues regarding the U.S. military's presence in South Korea and its transfer of wartime operational control to South Korea and United Nations forces there, Koh said.
South Korean President Moon Jae-in has accepted Kim's offer to meet near their shared border later next month, a meeting in which Kim was expected to suggested resuming cultural exchanges and family reunions. That session will provide more insight for the Trump-Kim meeting that South Korean National Security Council chief Chung Eui-yong said will take place by May.
The U.S. and the South Korea are also discussing how to conduct upcoming military drills in a way that won't provoke Kim, whose regime views the exercises as a rehearsal for war. The allies had agreed to delay the drills until after the Winter Paralympics end later this month. The South Koreans who met with Kim said he accepts that the next round of joint exercises will go ahead.
The U.S. is unlikely to deploy an aircraft carrier, which is considered a "strategic asset," during the drills, the Yonhap News Agency reported Monday. The South Korean Defense Ministry declined to comment on the planned drills.