He told reporters in Seoul on Wednesday that the country will take steps to disarm in two and a half years. But details of the agreement between President Trump and Kim Jong Un remain vague.
President Trump says he expects to know quickly whether North Korea is serious about surrendering its nuclear weapons. But Pyongyang has fooled the U.S. in the past.
Journalists observed as North Korea blew up tunnels it uses for nuclear testing. But experts say it was mostly for show, and closing the site will have little impact on the nation's capabilities.
"There's a chance, there's a very substantial chance that it won't work out," President Trump said of the June 12 summit with Kim Jong Un. Trump met with South Korea's president Tuesday.
President Trump tweeted out the details of his planned meeting with North Korea's leader. "I really think we have a very good chance of doing something very meaningful," he said.
As President Trump considers withdrawing from the Iran accord, Israel says files show Iran concealed its nuclear ambitions. But the U.K., France and Germany say they always knew that — hence the deal.
North Korea's leader told South Korea's president he would invite security experts and journalists to the site. South Korea's president also spoke with President Trump about a U.S.-North Korea summit.
"President Trump is in for a rude surprise if he thinks ... Kim Jong Un is going to say, 'Sure, I'll hand over my nuclear weapons,'" North Korea expert Jean H. Lee tells NPR.