The United States has been demanding the North free Kim Hak-song, Kim Sang-duk and Kim Dong-chul and reports have said the two sides were close to reaching a deal on their release.

“They are staying in a hotel on the outskirts of Pyongyang,” Choi Sung-ryong, a South Korean activist with contacts in the North said earlier.

He said the three were being kept separately but “going on tours, receiving medical treatment and eating good food.”

Diplomatic sources in Pyongyang have said there were rumours that the three had been relocated, but there had been no confirmation of their exact whereabouts.

A State Department official could not confirm the reports, but added: “We are working to see US citizens who are detained in North Korea come home as soon as possible.”

The matter was discussed when US Secretary of State Mike Pompeo travelled to Pyongyang last month, according to The Wall Street Journal.

And speaking to Fox News on Sunday, National Security Advisor John Bolton said releasing the hostages would be “an opportunity” for the North to “demonstrate their authenticity”.

CNN had said the prisoners’ release was also discussed at three-day talks in Stockholm between the North’s Foreign Minister Ri Yong-ho and Swedish counterpart Margot Wallstrom in March.

Sweden represents Washington’s interests in the North.

Tensions between North Korea and its neighbours as well as the US spiked last year over the Pyongyang’s testing of atomic weapons and long-range missiles, including some capable of reaching the US mainland.

But a spectacular detente in recent months, with a summit approaching between Trump and Kim, and the prospect of denuclearisation, have fed hopes of a historic turning point in the region.

Seoul and Pyongyang have remained technically at war since the 1950s but South Korean President Moon Jae-in and North Korean leader Kim Jong-un agreed at a landmark summit last week to work towards a permanent treaty to replace a 65-year-old armistice agreement.

As remarkable as the imagery and symbolism have been recently, many analysts point out that it is early to speculate on the outcome of ongoing negotiations with a regime that has been led with an iron fist by the Kim dynasty for nearly 70 years.

The three Americans held by North Korea 

Kim Dong-chul of Fairfax, Virginia, was arrested in October 2015 and sentenced to 10 years of hard labour in April 2016 on charges of spying and other offences.

A month before his trial, he supposedly apologised for trying to steal military secrets for South Koreans. He had been living in Rason, North Korea, in a special economic zone where he ran a trading and hotel services company.

Kim Sang-duk, or Tony Kim, was detained at the Pyongyang airport in April 2017 as he was set to depart the country. He subsequently was accused of “hostile acts”.

Kim had spent a month teaching accounting at Pyongyang University of Science and Technology and most recently had been living in North Korea with his wife, still believed to be there. He supposedly had been volunteering at an orphanage. 

The university is funded largely by evangelical Christians from the United States and China.

Kim Hak-Song was accused of “hostile acts” in May 2017. He had been doing agricultural development work at the research farm of Pyongyang University of Science and Technology and was living in Pyongyang.

Kim is an ethnic Korean born in China. He studied in California and became a US citizen in the 2000s but never forgot his roots. “He was a very diligent, hardworking man determined to help people in North Korea,” his friend David Kim told CNN.

North Korea has detained a range of visitors over the years, typically accusing them of undermining the state. Relations between the Washington and Pyongyang have grown particularly tense as North Korea has pushed ahead with a range of military tests that threaten their neighbour to the south.

Agence France-Presse, Tribune News Service, Reuters