This handout satellite image taken on Feb. 21 and released to AFP by Pleiades, Cnes 2019, Distribution Airbus DS on Feb. 28 shows the 5 MWe reactor at North Korea's Yongbyon Nuclear Scientific Research Center showing no signs of activity. / AFP-Yonhap

By Park Ji-won

Speculation is circulating over North Korea's secret nuclear facilities U.S. President Donald Trump mentioned amid rumors that one of the areas is a uranium enrichment facility called Kangson located near Pyongyang.

After failing to reach an agreement with North Korean leader Kim Jong-un, Trump held a press conference and said the U.S. told the North that it had found some hidden nuclear facilities, including a uranium enrichment plant, which likely surprised Kim.

"We had to have more than that because there are other things that you haven't talked about, that you haven't written about, that we found. And we have to have ― that was done a long time ago, but the people didn't know about," Trump said few hours after the summit was abruptly canceled without notice.

"And we brought many, many points up that I think they were surprised that we knew."

It appears that Trump asked the North to give up more than it was prepared to, including hidden facilities such as Kangson, adding these its Yongbyon facility if it wanted sanctions to be lifted. This was one of the main reasons for both sides to fail to narrow their differences during the summit.

"There are also timing and sequencing issues that were associated with that as well, which we didn't quite get across the finish line as well. But remember, too, even that facility, even the Yongbyon facility and all of its scope ― which is important, for sure ― still leaves missiles, still leaves warheads and weapons systems. So there's a lot of other elements that we just couldn't get to," U.S. Secretary of State Mike Pompeo added during the press conference.

It is widely believed that there are several other nuclear sites while Yongbyon is the only facility that North Korea has declared.

In 2018, open-source research identified a probable nuclear facility near Kangson. In the middle of June, last year, many U.S. news outlets went all-out to report the existence of the uranium processing site, citing U.S. intelligence agency's reports made since 2010. On Jan. 22, Japan's Asahi Shimbun also reported that a former senior officer at the South Korean presidential office who has dealt with North Korean nuclear issues and North-U.S. relations, told the media that when he was at the office, the U.S. authorities considered there were about 300 nuclear facilities in North Korea. According to the officer, the North has up to 10 uranium enrichment facilities, most of them underground near Pyongyang.

When asked what the facility that Trump mentioned was, Kim Yong-hyun, a professor at Dongguk University answered during a radio interview Friday, "We can think of two. One is an ICBM related facility, not the Yongbyon site. The other is a facility for highly enriched uranium (HEU)."

Woo Jung-yeop, a research fellow at the Sejong Institute in Seoul was quoted as saying to the Hankook Ilbo, the sister paper of The Korea Times, Thursday that the "uranium-related facility was easily hidden."

"Considering the fact that the North was surprised by Trump's revelation, we can reasonably assume that there are many nuclear facilities across the country apart from Kangson."