US President Donald Trump says he is prepared to meet North Korea's Kim Jong Un in what would be the first face-to-face encounter between the countries' leaders and potentially mark a major breakthrough in nuclear tensions with Pyongyang.
Kim has "committed to denuclearisation" and to suspending nuclear and missile tests, South Korea's National Security Office head Chung Eui-yong told reporters on Thursday after briefing Trump on a meeting South Korean officials held with Kim this week.
"A meeting is being planned," Trump posted on Twitter after speaking to Chung in the White House, setting up what would be his biggest foreign policy gamble since taking office.
Chung said Trump had agreed to meet by May in response to Kim's invitation. A senior US official said later it could happen "in a matter of a couple of months, with the exact timing and place still to be determined".
South Korean President Moon Jae-In, who led the pursuit of detente with North Korea during his country's hosting of the Winter Olympics last month, said the summit was a "historical milestone" that would put the denuclearisation of the Korean Peninsula "really on track".
Trump has previously said he was willing to meet Kim under the right circumstances but had indicated that the time was not right for such talks.
"Kim Jong Un talked about denuclearisation with the South Korean Representatives, not just a freeze," Trump posted on Twitter on Thursday night.
"Also, no missile testing by North Korea during this period of time.
"Great progress being made but sanctions will remain until an agreement is reached."
A meeting between Kim and Trump, who have exchanged bellicose insults in the past year that have raised fear of war, would be a major turnaround after a year in which North Korea has carried out a battery of tests aimed at developing a nuclear missile capable of hitting the US mainland.
Trump's aides have been wary of North Korea's diplomatic overtures because of its history of reneging on international commitments and the failure of disarmament efforts by previous US administrations.
US officials and experts had earlier cautioned that North Korea could buy time to build up and refine its nuclear arsenal if it managed to drag out any talks with Washington.
Japanese Prime Minister Shinzo Abe said he welcomed the change in North Korea's stance but pressure still needed to be applied on North Korea.
China's foreign minister, Wang Yi, called on the US and North Korea to hold talks as soon as possible, warning things "will not be smooth sailing".
A senior administration official told Reuters Trump had agreed to the meeting because it "made sense to accept an invitation to meet with the one person who can actually make decisions instead of repeating the sort of long slog of the past".
In a key North Korean concession, Chung said Kim understood "routine" joint military exercises between South Korea and the US must continue.