WASHINGTON — President Donald Trump agreed on Thursday to meet with North Korean dictator Kim Jong Un by May after Kim pledged to refrain from further nuclear tests and move toward denuclearization, according to South Korean officials.

The surprise announcement was made by South Korean National Security Advisor Chung Eui-Yong in a short statement outside the White House. The White House later said no firm timetable was set.

Chung said that in recent talks with South Korea, Kim Jong Un "expressed eagerness to meet President Trump as soon as possible."

A senior administration official said the sentiments from Kim were conveyed verbally to Trump during a briefing in the Oval Office at the White House Thursday, denying the existence of a physical letter from the South Korean envoys to the president, which was reported earlier.

The White House confirmed that Trump would accept Kim's invitation to meet, but a senior administration official told reporters on a call after the announcement that "at this point, we're not even talking about negotiations. What we're talking about is an invitation by the leader of North Korea to meet face to face with the president of the United States. The president has accepted that invitation."

Speaking anonymously on the call, the official offered insight into why the administration would take the historic step toward meeting: Because of Kim's consolidated decision making power in the regime, the senior official said "it made sense to accept an invite to meet with the one person who can actually make decisions" instead of continuing with the "long slog of the past."

In an earlier statement from press secretary Sarah Huckabee Sanders Thursday, the White House said "[W]e look forward to the denuclearization of North Korea. In the meantime, all sanctions and maximum pressure must remain.”

While the South Korean national security advisor set a May deadline during his announcement Thursday night, a senior administration official was more vague — telling reporters the time and place were "yet to be worked out" but that the meeting will come "in a matter of a couple months."

Prior to the announcement, Trump dropped by the White House press room to hint at the major announcement to come, suggesting that he was supportive.

The South Koreans were at the White House Thursday to brief U.S. National Security Advisor H.R. McMaster and other top officials on recent talks with the North Korean regime.

No sitting American president has ever met with a North Korean leader — although former president Jimmy Carter did visit the country in 1994 — and the meeting comes after months of blustering between the two unpredictable leaders.

Trump has called Kim "little rocket man," and threatened the country with destruction for its test; Kim has called Trump a "mentally deranged dotard," and has threatened to rain nuclear fire on the West.

But Chung credited Trump's "maximum pressure strategy" for forcing Kim to the diplomatic table.

Earlier this week, Pyongyang signaled its willingness to hold talks with Washington on denuclearization, saying it will suspend its nuclear tests while talks are underway.

Asked about the developments earlier this week, Trump expressed optimism, saying he believed overtures from the North Koreans were "sincere," attributing them to "very, very strong" sanctions and increased pressure from China.

The International Campaign to Abolish Nuclear Weapons, which won the Nobel Peace Prize in 2017, said in a statement after the announcement that "ICAN commends South Korea’s leadership in achieving history dialogue between the U.S. and North Korea, which is the only pathway to nuclear disarmament in the face of fire and fury."

The statement from Executive Director Beatrice Fihn continued, "We urge both North Korea and the United States to join the majority of countries in pursuing permanent denuclearization through The Treaty on the Prohibition of Nuclear Weapons."