U.S. President Donald Trump has accepted an invitation to meet North Korean leader Kim Jong Un by the end of May — a stunning and unexpected announcement that comes as the two historic adversaries dial back threats of nuclear annihilation and attempt to reach a deal on the issue of scrapping the North's nuclear weapons program.

"A meeting is being planned," Trump tweeted just hours after speaking to South Korean national security chief Chung Eui-yong, who announced that the U.S. leader had expressed a willingness to sit down with Kim "as soon as possible" in what will be his biggest foreign policy gamble since taking office.

"In our meeting, North Korean leader Kim Jong Un said he is committed to denuclearization," Chung said. "Kim pledged that North Korea will refrain from any further nuclear or missile tests. He understands that the routine joint military exercises between the Republic of Korea and the United States must continue. And he expressed his eagerness to meet President Trump as soon as possible.