U.S. President Donald Trump has agreed to meet with North Korean leader Kim Jong Un by May for a first-ever bilateral summit, U.S. and South Korean officials said Thursday, a move that may lead to a breakthrough on the North Korean nuclear issue.

Many countries welcome the historical decision, expressing hope that their dialogue will contribute to peace and stability in the Asia-Pacific region, but skepticism lingers about whether Pyongyang will really take concrete steps toward denuclearization.

Also, even if the summit is held, negotiations might break down as Kim could urge Trump to ensure North Korea's hereditary regime, ease sanctions and seek withdrawal of U.S. troops from the South in return for giving up nuclear weapons, analysts said.

A South Korean presidential source on Friday quoted Trump as saying Washington is willing to hold the summit after the planned inter-Korean summit in late April, between then and the end of May.

Trump said he "would meet Kim by May to achieve permanent denuclearization" in response to Kim's invitation to meet him "as soon as possible," South Korea's national security adviser Chung Eui Yong told reporters at the White House.

Chung, head of the National Security Office, made the remarks after briefing Trump about talks between senior South Korean officials and Kim earlier this week in Pyongyang.

The summit will take place "at a place and time to be determined," according to White House press secretary Sarah Huckabee Sanders. Speculation is growing that Trump and Kim may meet at a South Korean building in the truce village of Panmunjeom.

Chung quoted Kim as saying he is committed to denuclearization, and that North Korea will refrain from any further nuclear and missile tests, as well as he "understands" joint military exercises between the United States and the South must continue.

Trump said in a tweet "great progress being made," but stressed that sanctions on North Korea "will remain until an agreement is reached."

"Kim Jong Un talked about denuclearization with the South Korean representatives, not just a freeze" of the North's nuclear program, he wrote. "Also, no missile testing by North Korea during this period of time."

South Korean President Moon Jae, who has pledged to serve as a mediator between Washington and Pyongyang, on Friday voiced satisfaction with their agreement to hold the summit, saying a movement toward denuclearization will "go into higher gear," according to his office.

Trump's leadership will be "praised all over the world," Moon was quoted by the office as saying.

China, believed to have influence over Pyongyang as its main economic lifeline, said the country welcomes possible talks between the United States and North Korea, calling the recent move a "positive signal" from the two nations.

The situation surrounding the Korean Peninsula is "moving toward the right direction," Foreign Ministry spokesman Geng Shuang told a press conference, adding China will continue to make efforts to resolve Pyongyang's nuclear issue "through dialogue."

Japanese Prime Minister Shinzo Abe said he hailed the "change" in North Korea's stance, while Russia's state news agency Tass quoted Foreign Minister Sergey Lavrov as calling the envisioned U.S.-North Korean summit "the first step toward the right direction."

China and Russia, which share borders with North Korea, have argued the nuclear crisis should be resolved through dialogue.

U.S. and Japanese policymakers, meanwhile, are still trying to gauge Pyongyang's real intentions, amid uncertainty over whether it would really consider abandoning its hard-acquired nuclear capabilities. They have said Pyongyang has broken international promises several times.

During their telephone conversation following the U.S.-North Korea agreement to hold the summit, Trump and Abe confirmed the two nations will continue to maximize pressure on Pyongyang.

Trump and Abe "affirmed their strong intention to continue close trilateral coordination with South Korea to maintain pressure and enforce international sanctions until such point that North Korea takes tangible steps toward complete, verifiable, and irreversible denuclearization," the White House said.

The agreement for a Trump-Kim summit came after South and North Korea agreed to hold a meeting between Moon In and Kim in late April at Panmunjeom.

The two Koreas remain technically still at war because the 1950-1953 Korean War ended in an armistice instead of a peace treaty.

South Korea, the United States, Japan and other countries around the world remain fully and resolutely committed to the complete denuclearization of the Korean Peninsula, Chung said.

In a meeting Monday with a South Korean delegation led by Chung, the North Korean leader expressed openness to denuclearization talks with the United States and normalization of bilateral ties, according to South Korea.

Kim was quoted as saying he has no reason to possess nuclear weapons if nuclear threats against Pyongyang are removed and its security is guaranteed.

On Tuesday, Trump said North Korea seems to be "sincere" about engaging with Washington, and that U.S.-led sanctions, especially "the great help" from China -- the main economic lifeline of North Korea -- appear to have propelled Kim to seek dialogue with the United States.

Next Monday, Chung is expected to go to China and Suh Hoon, director of the National Intelligence Service, who was a member of South Korea's delegation, will visit Japan to brief the two governments on the meeting in Pyongyang.

(Photo courtesy of the South Korean presidential office)

Chronology of recent events concerning North and South Korea, and the United States:

July 4, 2017 -- North Korea succeeds for first time in test-firing intercontinental ballistic missile.

July 28 -- North Korea launches its second ICBM, unusually late at night.

Aug. 8 -- U.S. President Donald Trump warns he will counter North Korea with "fire and fury like the world has never seen" if the country further endangers the United States.

Sept. 3 -- North Korea conducts its sixth nuclear test.

Sept. 15 -- North Korea fires intermediate-range ballistic missile over Japan into the Pacific with flight distance of 3,700 kilometers, the longest yet, putting the U.S. territory of Guam within range.

Sept. 19 -- U.S. President Donald Trump, in his debut address to the U.N. General Assembly, calls North Korean leader Kim Jong Un "Rocket Man."

Sept. 22 -- Kim Jong Un reacts sharply to Trump's U.N. address in a rare statement, saying he will "surely and definitely tame the mentally deranged U.S. dotard with fire."

Oct. 1 -- Trump tells his top diplomat, Secretary of State Rex Tillerson, to stop "wasting his time" trying to negotiate with Kim Jong Un

Nov. 29 -- North Korea claims it successfully test-fired its new intercontinental ballistic missile capable of hitting anywhere in the United States with a nuclear warhead.

Jan. 1, 2018 -- Kim Jong Un, in New Year's address, says a nuclear button is always on his desk; Kim also expresses readiness to send athletes to Winter Olympics in Pyeongchang, South Korea.

Jan. 2 -- Trump ridicules Kim Jong Un over his nuclear button, saying the U.S. button is "much bigger and more powerful."

Jan. 4 -- The United States and South Korea agree to postpone annual joint military exercises until after Winter Olympics and Paralympics.

Jan. 9 -- North and South Korea agree at ministerial-level talks to the North sending athletes to the Olympics.

Feb. 9 -- North and South Korean athletes march together under a unified Korean flag at the Olympics' opening ceremony.

Feb. 10 -- South Korean President Moon Jae In and Kim Yo Jong, sister and close aide to Kim Jong Un, hold talks in Seoul. The North invites Moon to visit North Korea.

Feb. 23 -- The United States announces a slew of measures against North Korea that President Donald Trump called the "heaviest" sanctions ever imposed on the country.

Feb. 25 -- High-level North Korean official visits South Korea for Olympics' closing ceremony, meets with Moon in Pyeongchang.

March 5 -- South Korea's special envoys visit North Korea and hold talks with Kim Jong Un.

March 6 -- South Korea's presidential office unveils the outcome of the envoy's meeting with Kim Jong Un, including agreement of a summit meeting between the two Koreas in late April.

March 8 -- Senior South Korean official says Trump said he would meet Kim Jong Un by May to achieve denuclearization.

More on North Korea:

Denuclearization still unclear after Kim Jong Un's pledge

Inter-Korea summit breakthrough leaves Japan on back foot

China seeks early U.S.-N. Korea talks

Japan seeks use of anime to raise student awareness of abduction issue