Nearly 700 people tied to a Berlin religious institute are being investigated by German intelligence for possible espionage.

According to Germany’s BILD newspaper, the probe centers on the Al-Mustafa Institute, a Muslim school that opened in Berlin in 2016. Investigators are working through three classified lists: one naming 63 German citizens, another with 551 students connected to the Iranian parent university, and a third showing 78 German trainees.

On the outside, Al-Mustafa Institute maintains an innocent front, even running a PayPal page asking for donations to spread Islamic teachings in German-speaking areas. However, behind the religious facade, authorities found the university’s global branches were being used by Iran to gather intelligence and funnel support to terror groups like Hamas and Hezbollah.

Conservative members in Germany’s parliament are calling for Interior Minister Nancy Faeser to close the Institute.

“Iranian Islamist institutes on German soil should be closed immediately,” said Christian Democratic Union MP Christoph de Vries. “Why hasn’t the interior ministry closed the Mustafa Institute in Berlin long ago, while the organization has been on the sanctions lists in the USA and Canada for years?”

Last Thursday, Germany ordered Iran’s three consulates to cease operations in retaliation for Tehran’s execution of Iranian-German dual citizen Jamshid Sharmahd. Sharmahd, 69, who had been living in the United States, was executed Monday on terrorism charges after what international observers widely condemned as a show trial.

Iran charged that Sharmahd, from his home in suburban Los Angeles, ordered a bloody mosque bombing that killed 14 people back in 2008. Among the dead were five women and a child, with over 200 others wounded in the blast. Prosecutors tied him to an obscure militant group called Tondar, linked to the Kingdom Assembly of Iran.

Before ordering the consulate closures, Germany had summoned Iran’s charge d’affaires to protest the execution. Berlin also recalled its ambassador, Hans-Udo Muzel, after his formal protest to Iranian Foreign Minister Hossein Amir-Abdollahian fell on deaf ears.