A U.S. think tank says it has uncovered what it believes to be a covert North Korean military base near the Chinese border, likely housing intercontinental ballistic missiles(ICBMs) capable of reaching the U.S. mainland. 

Experts from the Center for Strategic and International Studies presented the assessment on Beyond Parallel, a website on North Korea run by the center.

In a report released Wednesday, the center’s experts said they have identified a secret base near the village of Sinpung-dong, about 27 kilometers from the Chinese border.

The report said preliminary analysis of satellite imagery from July 11 suggests that the base likely houses a brigade-sized unit equipped with a total of six to nine nuclear-capable Hwasong-15 or -18 ICBMs, or an as yet unknown ICBM, and their transporter-erector-launchers or mobile-erector-launchers.

The report also said these missiles pose a potential nuclear threat to East Asia and the continental United States, adding that the base is one of approximately 20 ballistic missile bases, maintenance facilities, support facilities, missile storage facilities and warhead storage facilities that North Korea has never declared.