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A NATO summit in Ankara, Turkey on July 7. NATO’s 2022 Strategic Concept document notes that China poses ‘systemic challenges’ to Euro-Atlantic security.Hussein Malla/The Associated Press

Belgian authorities suspect a Canadian NATO intern arrested on suspicion of espionage was working for China, according to two sources with knowledge of the case.

In announcing her arrest on Saturday, Belgian prosecutors said the woman worked at NATO’s military headquarters in the city of Mons and was a “Canadian national of Chinese origin” suspected of spying for a third country and belonging to a criminal organization.

They did not name the country or the organization. But the two sources, speaking on condition of anonymity to discuss a confidential investigation, told Reuters the country under suspicion was China.

The Chinese Foreign Ministry did not immediately reply to a request for comment faxed outside business hours. The Chinese embassy in Brussels did not immediately reply to an e-mailed request for comment.

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NATO’s 2022 Strategic Concept document, the foundation of the military alliance’s policies, says China poses “systemic challenges” to Euro-Atlantic security. In response, China’s foreign ministry accused NATO of groundless accusations, smears and attacks.

A security source said the woman, identified as Claire Z, is in her 30s and not a student. She arrived in Mons about a year ago to start her internship with NATO’s Supreme Headquarters Allied Powers Europe, or SHAPE, where she worked in the IT department, the source also said.

She registered in Belgium as single without children, the source said.

Zhang did not immediately reply to messages sent to social media accounts matching her description. She has not made any public comment on the allegations against her, nor has any lawyer acting on her behalf.

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According to a LinkedIn profile that the source confirmed was that of the suspect, Claire Z. previously worked at the European Space Agency and the World Trade Organisation.

Asked about the case, the ESA said a position with the agency does not require a personal security clearance but it applies its standard human resources screening procedures. They referred to Belgian authorities for further questions. The WTO did not immediately reply to a request for comment.

On Tuesday, prosecutors said Z.’s pretrial detention had been extended by one month. A spokesperson said on Thursday that Zhang had appealed the decision, with a ruling on the appeal expected within the next two weeks.

Responsibility for conducting security checks on NATO interns lies with their countries of origin, which in this case was Canada.

Canada’s Minister of Public Safety Gary Anandasangaree said earlier this week that authorities would review the country’s security screening process, adding it was important “to get to the bottom of what happened.”

SHAPE reported the suspect to Belgian intelligence after observing her behaviour, according to Belgium’s prosecutors’ office. A SHAPE spokesperson has said there was no indication the incident had affected NATO’s operational readiness, command and control, or ongoing missions.