BRUSSELS — A Canadian woman was arrested and accused of espionage while working as an intern in the operational headquarters of the NATO military alliance, Belgian authorities said Saturday.

Belgium’s Federal Prosecutor’s Office said it launched an espionage investigation after NATO’s security services tipped off Belgium’s military intelligence. Authorities then detained “a Canadian citizen of Chinese origin” on Friday, a day after raiding the suspect’s home and workplace inside NATO’s vast command center.

“She is suspected of spying on behalf of a third country and of being a member of a criminal organization,” the prosecutors said in a statement.

The strategic headquarters of the Allied Powers, known as SHAPE, is located in the southern Belgian city of Mons near the French border. Military officials at SHAPE plan and command joint strategy, tactics and operations. The alliance’s political headquarters is in Brussels, where ambassadors from member nations meet to discuss defense spending, drone incursions and cyber threats. NATO’s Cyber Security Centre is based at SHAPE.

Both Canada and Belgium are members of the 32-nation military alliance that in 2021 labeled China a “ security challenge ” alongside active threats in Russia and the Middle East.

NATO leaders have said China is working to undermine global order, develop its military opaquely, and run destabilizing disinformation campaigns. They said that Beijing’s goals and “assertive behavior present systemic challenges to the rules-based international order and to areas relevant to alliance security.”

The Chinese government denounced the statement and said its military buildup was defensive.

The arrest in Belgium comes at a crucial time for the alliance as it weathers deep criticism from President Donald Trump who has drawn down the U.S. security role in Europe. Trump has been pressing allies to spend more on defense and join the conflict in Iran while at the same time threatening to seize by force Greenland from NATO-member Denmark, a move that rattled Europeans and the alliance.

Last year, following pressure from Trump, 32 NATO nations agreed to invest 5% of their gross domestic product on defense — 3.5% on defense items such as jets and missiles and 1.5% on infrastructure, including roads, bridges and ports, as well as cybersecurity.