US President Donald Trump is set to visit South Korea as an exchange of letters with North Korean leader Kim Jong-un boosted hopes for talks aimed at ending North Korea’s nuclear program.

Trump is set to arrive in South Korea for a two-day visit on Saturday, and will meet President Moon Jae-in on Sunday following a summit of G20 leaders in Japan, Moon’s spokeswoman Ko Min-jung said.

The announcement comes hours after US Secretary of State Mike Pompeo said he hoped a letter Trump sent to Kim could pave the way for a revival of stalled nuclear talks.

Trump and Moon would have “in-depth discussions on ways to work together to foster lasting peace”, Ko told a news briefing on Monday.

Trump told reporters at the White House on Monday that Kim had sent him birthday wishes.

“It was just a very friendly letter both ways. We have a very good relationship,” he said.

Pompeo, who spoke of Trump’s letter to Kim before departing from Washington for the Middle East, said the US was ready to resume talks with North Korea immediately.

“I’m hopeful that this will provide a good foundation for us to begin … these important discussions with the North Koreans,” Pompeo told reporters.

Trump is considering a visit to the demilitarised zone (DMZ) separating the two Koreas, a South Korean official said.

Trump wanted to go there during a 2017 trip to South Korea but heavy fog prevented it.

Kim and Moon held their historic first summit in the DMZ last year, so a Trump visit to the border between the two Koreas this weekend could spark speculation of a meeting with Kim there.

Another official in the South Korean presidential office said she was not aware of any plan for Trump to meet Kim.

North Korea’s state news agency KCNA said on Sunday Kim had received a letter from Trump, which he described as being “of excellent content”, but did not disclose any details.

KCNA said Kim “would seriously contemplate the interesting content”.

Shin Beom-chul, a senior fellow at the Asian Institute for Policy Studies in Seoul, said Trump may have proposed a new round of working-level talks but a major breakthrough was not likely for now.

“North Korea has to show what the final state of denuclearisation would look like and what roadmap it has toward that end, but it’s not desirable to reopen talks just to manage the situation after recent weapons tests,” Shin told Reuters.