Seven Chinese nationals were apprehended on allegations of unlawfully entering Guam coinciding with a significant missile interception test conducted by the U.S. Missile Defense Agency utilizing a new radar system, according to the island’s Customs and Quarantine Agency. The agency reported that at least four of those detained on December 10-11 were located “in the vicinity of a military installation.” Guam is home to numerous such facilities, including Andersen Air Force Base, where the missile test took place on December 10.

The Institute for the Study of War noted in a report released on Friday that “conducting espionage against U.S. military facilities, particularly those capable of missile launches, could yield valuable intelligence for the PRC.” Authorities in Guam indicated that all the Chinese individuals arrived on the same vessel from Saipan, and the investigation is still ongoing. China’s Ministry of Foreign Affairs has yet to respond to a request for comment.

The United States is set to establish an air and missile defense network across 16 locations on the island to deter potential missile threats by complicating and increasing the resources required for such attacks. This initiative aims to incorporate the most advanced U.S. missile defense systems and radar technology, with projected costs reaching up to $10 billion over the next ten years. The missile test conducted on December 10 was deemed successful, and the Missile Defense Agency anticipates conducting up to two interception tests annually.