Thirteen undeclared North Korean missile operating bases were identified in a new report which undermines the Trump Administration's claims that its outreach to Pyongyang is making progress in getting Kim Jong Un's regime to give up its nuclear weapons programme.
The 13 sites are among an estimated 20 bases, which are small and dispersed across the country, that are believed to have underground facilities containing mobile launchers that can be quickly dispersed to other locations, according to the report from Beyond Parallel, a group at the Centre for Strategic and International Studies in Washington.
Although not designed as launch sites, the bases could be used to launch short-range as well as intercontinental ballistic missiles.
"The dispersed nature, small size of operating bases, and tactics and doctrine employed by ballistic missile units provide the best chances for their survival given the KPA's technology and capabilities," according to the report, using an acronym to refer to the Korean People's Army.
The existence of the bases - which presumably would have to be declared and then dismantled under the US goal of North Korean "denuclearisation" - suggests that North Korea's previous efforts to dismantle known missile launch sites or nuclear facilities had little impact on its nuclear programme.
The report comes as talks between the US and North Korea hit another snag last week, with a New York meeting between Secretary of State Michael Pompeo and the top negotiator from Pyongyang cancelled at the last minute.
US President Donald Trump - who's cited North Korea's year-long freeze on nuclear weapons tests and ballistic missile launches as signs of progress - chalked up the change to a scheduling conflict, adding, "We think it's going fine, we're in no rush."
Yet pressure is building to ease international sanctions put in place last year, a move the Trump Administration is struggling to resist.
Last week, Russia called a meeting of the United Nations Security Council to take up its request for humanitarian exemptions to international sanctions on Pyongyang. The US said it would vet Russia's list, but Administration officials have previously said Moscow is already violating the restrictions.
The facilities identified in the new report are located in strategic locations that would put missiles in range of South Korea and Japan, according to the report. Some are likely to house missiles that could reach the continental US when they become deployed. For decades, the bases have been camouflaged to prevent destruction from pre-emptive strikes and during military operations.
The report singled out a base known as Sakkanmol, about 80km north of the demilitarised zone and one of the closest to South Korea.
The base, located in mountainous terrain, contains a unit equipped with short-range ballistic missiles, the report said, and could house medium-range ones. As of this month, "the base is active and being reasonably well-maintained by North Korean standards" with minor infrastructure changes.