Three upcoming concerts by Taylor Swift in Vienna have been cancelled after a possible security threat.

The concerts, part of Swift’s Eras tour, were scheduled for Thursday, Friday, and Saturday at the Ernst Happel Stadium.

On Wednesday, Austrian authorities arrested two people suspected of planning Islamist attacks on large events near Vienna.

The organisers of the concerts issued a statement saying, “Due to confirmation by government officials of a planned terrorist attack at the Ernst Happel Stadium, we have no choice but to cancel the three planned shows for everyone’s safety.”

The statement added, “All tickets will be automatically refunded within the next 10 working days.”

Austria’s General Director for Public Security, Franz Ruf, reported that a 19-year-old Austrian was arrested in Ternitz, Lower Austria, on Wednesday morning. Another suspect was arrested in Vienna later that day.

Ruf explained, “According to the current status of the investigation, the two suspects became radicalised via the internet.”

He also noted that the 19-year-old had pledged allegiance to the so-called Islamic State at the beginning of July. A large police operation in Ternitz included evacuating nearby houses and searching the suspect’s home. “Chemical substances had been found and are being examined,” Ruf said.

Austrian Chancellor Karl Nehammer commented on the situation, saying, “The cancellations would be a bitter disappointment for all fans but the situation was very serious.” He praised the cooperation of police and security agencies, saying, “Thanks to the intensive cooperation of our police and [security agencies] with foreign services, the threat was recognized early, combated and a tragedy prevented.”

Vienna police chief Gerhard Pürstl said the concerts were expected to draw 65,000 people each day, with an additional 22,000 fans outside the venue. Investigations are still ongoing.