The suspects in the foiled plot to attack Taylor Swift’s Eras Tour concerts in Vienna earlier this month wanted to kill “tens of thousands” of the artist’s fans, CIA Deputy Director David Cohen said Wednesday at a security conference in Maryland.

“They were plotting to kill a huge number — tens of thousands of people at this concert, including, I am sure, many Americans — and were quite advanced in this,” Cohen said, according to The Associated Press. “The Austrians were able to make those arrests because the agency and our partners in the intelligence community provided them information about what this ISIS-connected group was planning to do.”

Swift’s Vienna concerts, which would have begun on Aug. 8, were canceled by the events’ organizers, Barracuda Music, when they were informed of the foiled plot by Austrian authorities.

The move left tens of thousands of Swift’s fans, many of whom had traveled to Vienna from elsewhere in the country or abroad specifically to see a show, devastated.

“I won’t be able to see Taylor again with these resale prices so I am pretty devastated,” one social media user named Caroline said shortly after the shows were canceled. “This was supposed to be my ‘you beat cancer’ trip so losing it hurts.”

Another social media user named Sarah wrote that she had been “waiting to see taylor in my home country since i was 9 years old, i’m now 25… to have all this taken away by some men being so fueled by hatred for no reason at all makes me so beyond angry i can’t put it into words.”

The main suspect in the alleged plot, along with a 17-year-old, were taken into custody on Aug. 6, the day before the cancelations were announced. Austrian officials said the primary suspect, who they have not named due to Austrian privacy laws, was inspired by ISIS. They said he had planned to attack outside the stadium with knives or explosives.

A third suspect, who was 18 years old, was arrested on Aug. 8.

At the security conference Wednesday, CIA Deputy Director Cohen praised the CIA’s work, saying counterterrorism “successes” often go unheralded, according to the AP.

“I can tell you within my agency, and I’m sure in others, there were people who thought that was a really good day for Langley,” he said, referring to the location of the CIA headquarters in Virginia. “And not just the Swifties in my workforce.”