“The North Koreans are not going to negotiate over things they don’t disclose,” said Victor Cha, one of the authors of the report. “It looks like they’re playing a game. They’re still going to have all this operational capability,” even if they destroy their disclosed nuclear facilities.

Cha says the base is “clearly a mainstay of their strategic missile force,” but there are no indications it is part of any discussions on denuclearization.

Situated about 130 miles north of the DMZ, Sino-ri Missile Operating Base houses the headquarters for the Korean People’s Army Strategic Rocket Forces missile brigade, a unit responsible for ballistic missiles. The base has been central to developing ballistic missiles that are capable of reaching South Korea, Japan, and even Guam, according to the report.