A leading North Korea-watching website has disputed Foreign Minister Taro Kono’s reported remarks that Pyongyang is preparing to conduct a fresh nuclear test even as tensions on the Korean Peninsula ease ahead of a rare summit between the two Koreas.

Kono claimed Saturday during a lecture in the city of Kochi that North Korea is “working hard to get ready for the next nuclear test,” citing satellite imagery. But an analysis published Monday by the 38 North blog at the U.S.-Korea Institute at Johns Hopkins University’s School of Advanced International Studies disputed his claim that soil had been removed from a tunnel at a site where tests had been conducted in the past.

“While it is unclear whether the foreign minister was referring to activity observed over the last few days or from earlier work conducted after North Korea’s September 2017 nuclear test, commercial satellite imagery from March 23 shows quite a different picture: namely, that activity at the test site has been significantly reduced compared to previous months,” the report said of activity at the North’s main Punggye-ri nuclear test site.

Asked Tuesday about the 38 North analysis, Kono pointed to an increase in roadwork at the Punggye-ri site that was noted in the report, but did not address the issue of soil removal.

Monday’s analysis noted that, despite the slowdown, it remains highly likely that the North Koreans continue to maintain the readiness of Punggye-ri to allow for nuclear testing in the future should Pyongyang decide to do so.

Considering a variety of information released, “I believe that activities at the nuclear facilities — including the test site — are continuing,” Kono said Tuesday.

Media reports quoting his Kochi lecture had suggested his remarks may have been based on satellite imagery provided by the United States.

Tunneling at the west portal — a site not associated with any of North Korea’s previous nuclear tests — was active earlier this year but has dwindled, as has other personnel and vehicular movement around the site.

In the previous analysis of imagery at the site taken earlier last month and published March 23, the website said activity at Punggye-ri had seen a “significant slowdown” as high-level talks between North and South Korea moved forward, and U.S. President Donald Trump accepted an apparent invitation from North Korean leader Kim Jong Un to meet sometime before the end of May.

North Korea conducted its sixth nuclear blast — its most powerful to date — last September, in what it claimed was a test of a thermonuclear weapon.