U.S. President Donald Trump has accepted an offer of a summit from the North Korean leader and will meet with Kim Jong-un by May, a top South Korean official said Thursday, in a remarkable turnaround in relations between two historic adversaries.

Speaking Thursday night outside the White House, Chung Eui-Yong, South Korean national security director, said that Kim had requested the meeting.

Watch the full statement from the South Korean security official.

Kim Jong-un and Donald Trump to meet by May2:16

The South Korean official told reporters Trump said “he would meet Kim Jong-un by May to achieve permanent denuclearization.”

Chung said Kim pledged that “North Korea will refrain from any further nuclear or missile test.”

The Republic of Korea, the U.S. and partners are standing together to avoid repeating the mistakes of the past, the South Korean said.

“The pressure will continue until North Korea matches its words with concrete actions.”

Trump responded on Twitter not long after the press briefing, saying that the meeting is being planned and that sanctions would stay in place until an agreement is reached.

While he was speaking to reporters who had gathered to hear the news, Chung said that Trump’s “maximum pressure policy” and leadership, along with international solidarity, had brought the countries to this point.

White House spokesperson Sarah Sanders said in a statement that Trump appreciated South Korea’s words and accepted the invitation.

A spokesperson for Foreign Affairs Minister Chrystia Freeland’s said in a statement that Canada has “always believed that a diplomatic solution to the North Korean nuclear crisis is essential and possible.”

Canada and the U.S. recently co-hosted a summit in Vancouver to discuss efforts to find a peaceful path to deal with North Korea’s nuclear and ballistic weapon programs.

Seoul has previously publicized that North Korea offered talks with the United States on denuclearization and normalizing ties, a potential diplomatic opening after a year of escalating tensions over the North’s nuclear and missile tests. The rival Koreas also agreed to hold a leadership summit in late April.

Top Trump administration officials got a chance to hear firsthand from South Korean national security director, Chung, who led the delegation that went to Pyongyang and met Kim on Monday.

North Korea Koreas Tensions

Kim Jong-un, front right, shakes hands with South Korean national security director Chung Eui-yong in Pyongyang Monday. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. (Korean Central News Agency/Associated Press)

Chung told reporters on Tuesday that he received a message from North Korea intended for the United States but didn’t disclose what it was. 

Not long ago, Trump and Kim were trading barbs, with Kim once calling the U.S. president a “mentally deranged U.S. dotard.” 

Trump, who has called Kim “little rocket man” and a “madman” threatened at one point to unleash “fire and fury like the world has never seen” should North Korea continue to threaten the U.S.

On Tuesday, Trump had expressed both hope and scepticism about the reported offer of talks. While the path to a diplomatic resolution over the North’s nuclear arsenal would be long and difficult, talks could dampen fears of war breaking out over what represents an emerging threat to the U.S. mainland.

House foreign affairs committee chairman Ed Royce, a Republican, said in a statement Thursday night that Kim’s openness to talks shows the “sanctions the administration has implemented are starting to work.” 

But he also had a note of caution, saying, “We can pursue more diplomacy, as we keep applying pressure ounce by ounce. Remember, North Korean regimes have repeatedly used talks and empty promises to extract concessions and buy time.” 

U.S. Secretary of State Rex Tillerson, speaking before the Thursday night announcement, said from iEthiopia that the U.S. has seen “potentially positive signals” from North Korea, but the adversaries are still a long way from holding negotiations