“The main suspect had sworn an oath of allegiance to IS on the internet and chemical substances were seized in his apartment during a house search,” the authorities added.
Pop star Swift was supposed to play three shows in Austria as part of the European leg of her sell-out Eras tour.

Organizers said Wednesday that the shows had been canceled as a precaution in response to the terror threat.
“With confirmation from government officials of a planned terrorist attack at Ernst Happel Stadium, we have no choice but to cancel the three scheduled shows for everyone’s safety,” Barracuda Music said in a statement on Instagram.
Barracuda added that all ticketholders would be refunded. A notice on Swift’s official website says refunds will be processed “within the next 10 business days.”
Ernst Happel Stadium is Austria’s largest concert venue, seating over 50,000. Vienna was the second-to-last stop on Swift’s European tour. She is set to perform at London’s Wembley Stadium next week before jetting off to Canada.