President Donald Trump has accepted an invitation to meet with North Korean leader Kim Jong Un by May, setting in motion the most significant development in years of intermittent negotiations about North Korea's nuclear weapons program.

The invitation to meet was delivered in person by a South Korean envoy who met with Trump and key national security officials in the Oval Office on Thursday, according to a senior administration official who briefed reporters following the announcement.

Speaking outside the White House, South Korea's National Security Office head Chung Eui-yon said Kim "expressed eagerness to meet President Trump as soon as possible."



Kim has also pledged that his country will "refrain from any further nuclear or missile tests" while talks are underway, Chung said. "President Trump appreciated the briefing, and said he would meet him to achieve permanent denuclearization."

Both the time and place have yet to be discussed, said the administration official, who emphasized that the development was just a meeting, and not a promise of sanctions relief or concessions from the United States.

"We're not even talking about negotiations," he said.

"The president is not prepared to reward North Korea in exchange for talks, but he's willing to meet and he expects North Korea to start putting action to these words," the official said.

In the long term, the United States "will settle for nothing less than denuclearization. It's what we expect and what the world expects," he added.