WASHINGTON ¨C One of 20 undeclared ballistic missile operating bases in North Korea serves as a missile headquarters, according to a report by the Center for Strategic and International Studies (CSIS) published on Monday.

¡°The Sino-ri missile operating base and the Nodong missiles deployed at this location fit into North Korea¡¯s presumed nuclear military strategy by providing an operational-level nuclear or conventional first strike capability,¡± the report said.

The discovery of an undeclared missile headquarters comes three days after U.S. President Donald Trump announced on Friday that he ¡°looks forward¡± to another summit to discuss denuclearization with North Korean leader Kim Jong Un in late February.

CSIS, which last reported on the 20 undeclared bases in November, said the Sino-ri base has never been declared by North Korea and as a result ¡°does not appear to be the subject of denuclearization negotiations.¡±

The report noted that missile operating bases would presumably be subject to declaration, verification and dismantlement in any denuclearization deal.

¡°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.

Located 132 miles (212 km) north of the demilitarized zone, the Sino-ri complex is a 7-sq.-mile (18-sq.-km) base that plays a key role in developing ballistic missiles capable of reaching South Korea, Japan, and even the U.S. territory of Guam in the Western Pacific, the report said.

It houses a regiment-sized unit equipped with Nodong-1 medium-range ballistic missiles, the report added.

The White House did not immediately respond to a request for comment.

Satellite images of the base from Dec. 27 show an entrance to an underground bunker, reinforced shelters and a headquarters, the report said.