Kim had “committed to denuclearization” and to suspending nuclear and missile tests, South Korea’s National Security Office head Chung Eui-yong told reporters at the White House on Thursday after briefing Trump on a meeting South Korean officials held with Kim earlier this week.

Kim and Trump have engaged in an increasingly bellicose exchange of insults over the North’s nuclear and missile programs, which it pursues in defiance of U.N. Security Council resolutions, before an easing of tension coinciding with last month’s Winter Olympics in the South.

“A meeting is being planned,” Trump said on Twitter after speaking to Chung, setting up what would be his biggest foreign policy gamble since taking office in January 2017.

Chung said Trump agreed to meet by May in response to Kim’s invitation. A senior U.S. official said later it could happen “in a matter of a couple of months, with the exact timing and place still to be determined.”

Both Russia and China, who joined years of on-again, off-again “six-party” talks, along with the United States, the two Koreas and Japan, aimed at ending the standoff, welcomed the new, positive signals after months of deteriorating relations between North Korea and the United States.

Trump has derided the North Korean leader as a “maniac,” referred to him as “little rocket man” and threatened in a speech to the United Nations last year to “totally destroy” Kim’s country of 26 million people if it attacked the United States or one of its allies.

Kim responded by calling the U.S. president a “mentally deranged U.S. dotard.”

South Korean President Moon Jae-In, who led the pursuit of detente with North Korea during his country’s hosting of the Winter Olympics, said the summit would set a course for denuclearization, according to a presidential spokesman. Trump had agreed to meet Kim without any preconditions, another South Korean official said.

Asian stock markets rose on the news, with Japan's Nikkei .N225 ending up 0.5 percent and South Korean stocks .KS11 more than 1 percent higher. The dollar also rose against the safe-haven Japanese yen JPY=. U.S. stock index futures were little changed ahead of the market's open Friday morning. [MKTS/GLOB]

“It’s good news, no doubt,” said Hong Chun-Uk, chief economist at Kiwoom Securities in Seoul. “But this will likely prove to be only a short-lived factor unless more and stronger actions follow.”

Trump had previously said he was willing to meet Kim under the right circumstances but had indicated the time was not right for such talks. He mocked U.S. Secretary of State Rex Tillerson in October for “wasting his time” trying to talk to North Korea.