A report by a major think tank on North Korea’s missile program has created a sensation while U.S. officials wonder what’s next in efforts at reconciliation and dialogue with North Korea.

The report, issued by the influential Center for Strategic and International Studies, cites as many as 20 facilities that could be used launching short-range, intermediate-range and long-range ballistic missiles. Satellite imagery has detected more than half the sites that are in various stages of construction and development.

The report is increasing doubts in Washington about whether it’s possible to reach any accommodation with North Korea on its program for building nuclear warheads and the long-range missiles needed to carry them to distant targets. CSIS released the report in the midst of efforts at arranging a second summit between President Donald Trump and North Korea’s leader, Kim Jong-un.

Analysts say the report is showing overwhelming differences between pledges of “denuclearization” made by Trump and Kim at their summit in Singapore in June and the reality that North Korea has done nothing substantive about getting rid of its nukes and missiles. As the report makes clear, the North Koreans have acknowledged the existence of none of these sites. Nor have they provided an inventory on their nuclear and missile program.

The report delivered a devastating indictment of North Korea for its efforts at avoiding detection while making a pretense of seeking reconciliation through dialogue.

In fact, said the report, “The dispersed deployment of these bases and distinctive tactics employed by ballistic missile units are combined with decades of extensive camouflage, concealment and deception practices.” The point, it said, was to maximize the survival of its missile units from pre-emptive strikes and during wartime operations.”

The report zeroed in specifically on the Sakkanmol missile base 85 kilometers north of the Demilitarized Zone, stating that it is now equipped with short-range ballistic missiles capable of reaching much of Japan and anywhere in South Korea. The site, says the report, “could easily accommodate more capable medium-range ballistic missiles.”

South Korean officials insisted the report basically had no new information, that all its findings were well known to South Korean and American analysts, but the report was still likely to have a devastating effect on the mood here about making further concessions to North Korea. While North Korea has demanded the United States remove sanctions imposed for its nuclear and missile tests, Trump has repeatedly said sanctions will remain in place until North Korea makes good on the promises made at Singapore.

U.S. officials do not consider North Korea’s gesture of blowing up its nuclear test site at Pyunggye-ri as convincing since the site was largely destroyed in the North’s last missile test more than a year ago. North Korea has said inspectors are welcome to take a look at the site, but no one seems very interested in taking up the offer.

Opinions vary widely as to how far the North Koreans have gone in developing the sites, all of them spread out over mountainous regions where detection and monitoring, even by satellites, is quite difficult. Images of the Sakkanmol site indicate support buildings scattered over a wide area while the missiles themselves are hidden in tunnels.

Joseph Bermudez, who has written extensively on North Korea’s missile program for years, is quoted in the report as emphasizing that the bases are “not launch facilities” but also said that “missiles could be launched from within them in an emergency.

Bermudez derided North Korea’s decision to shut down its Sohae site near the Chinese border for launching satellites as basically a play “for gaining media attention.” At the same time, he said, that gesture “obscures the military threat to U.S. forces and South Korea from this and other undeclared ballistic missile bases.”

The report was expected to have an immediate effect on attempts to revive talks between Secretary of State Mike Pompeo and North Korea’s Kim Jong-chol. In fact, some observers believed it was because they knew the report was about to be released that North Korea canceled a meeting the two were to have had last week at which they were to discuss arrangements for another summit between Trump and Kim early next year.

South Korean officials feared the report would derail the drive toward reconciliation not only between the two Koreas but also between the United States and North Korea. It was to stave off the negative effect that Kim Eui-kyeom, spokesman for the  Blue House, observed that South Korea and the United States  had “far more detailed information from military satellites.”

Moreover, he noted, the Sakkanmol base was for short-range missiles, not for the long-range types that most alarmed the United States last year when Trump denounced Kim as “little rocket man.”