A deputy chief of the CIA revealed that a foiled terrorist attack aimed at a Taylor Swift concert in Vienna earlier this month was designed to cause mass casualties, targeting “tens of thousands” of concert-goers.

David Cohen, the CIA’s deputy director, discussed the terror plot targeting Swift’s fans during the annual Intelligence and National Security Summit in Maryland, as reported by the Associated Press and The New York Times.

“They were scheming to inflict significant harm, potentially on tens of thousands, and I’m sure many Americans would have been among them, and they were quite advanced in their plans,” Cohen stated on Wednesday. “Thanks to the collaboration of our agency with partner intelligence organizations, the Austrians were able to detain the suspects connected to this ISIS-linked group.”

In connection with the foiled attack, three individuals were arrested ahead of one of Swift’s concerts scheduled for August 8-10 in Vienna, which were ultimately canceled. The suspects include an 18-year-old Iraqi, a 19-year-old Austrian from a town near Hungary, and a 17-year-old who was hired by a contractor for services at the Ernst Happel Stadium.

Austria’s Chancellor Karl Nehammer stated via social media that the threat level was very high and a disaster had been averted.

“We had no option but to cancel all three concerts to ensure everyone’s safety,” said Barracuda Music, the promoter for these Austrian events. “All ticket holders will be reimbursed automatically over the next 10 business days.”

Swift addressed the situation in an Instagram post on August 21, discussing the canceled concerts and the implications for her fans’ safety.

“The cancellation of our Vienna shows was heartbreaking. Learning the reason behind it filled me with new fears and an overwhelming sense of guilt since many were eagerly looking forward to attending,” Swift shared. “However, I am incredibly thankful to the authorities, for their actions meant we were mourning canceled concerts rather than lives lost.”

She added: “The solidarity and love I saw among fans was uplifting. I shifted all my focus to ensuring the safety of the nearly half a million people planning to attend shows in London. My team collaborated closely with stadium staff and UK authorities every day to achieve this. I am grateful for all their efforts on our behalf.”

Contributing: Bryan West, Taijuan Moorman, KiMi Robinson, Edward Segarra