Authorities had earlier confirmed the arrest of a 19-year-old sympathiser of the armed group for allegedly planning an attack in the Vienna region, warning he had a “focus” on Swift’s three upcoming shows.

“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 on Instagram.

The organisers added that all ticket holders would receive refunds. About 65,000 spectators were expected at each show scheduled for Thursday, Friday and Saturday.

The man, who had pledged his allegiance to IS “in recent weeks”, was detained in Lower Austria about an hour from the capital early on Wednesday, Austria’s top security chief Franz Ruf told a press conference.

“We have established corresponding preparatory acts and also that there is a focus of the 19-year-old perpetrator on the Taylor Swift concerts in Vienna,” Ruf said.

He said that chemical substances had been seized at the suspect’s home.

A second person believed to have been in contact with the suspect was arrested in Vienna.

According to the initial investigation, both suspects radicalised themselves on the internet.

Police had promised to ramp up security measures, including deploying special units for the concerts, while having minimised any concrete danger.

‘Shocked, sad’

In the official “Swifties” fan group on WhatsApp, panic ensued following the announcement of the shows’ cancellation with administrators overwhelmed with thousands of messages.

Marie Sereinig, 15, who had travelled from the south of the Alps to attend the show with her aunt, had spent months planning her outfit for the concert.

“I’m simply shocked and very sad. But I can also understand that Taylor Swift wouldn’t dare go on stage in these conditions,” she told AFP.

Other fans also shared their dismay.

“I don’t really have any words,” said Flora Zoe Koberwein, a 20-year-old student, adding, “sorry for those who have travelled so far”.

Conservative Chancellor Karl Nehammer called the cancellation “a bitter disappointment” for fans in a post on X, adding that the “very serious” threat had been combatted early to prevent any tragedy.

The 34-year-old pop star was due to bring her record-breaking “Eras” Tour, which began its European leg in Paris in May, to Vienna on Thursday.

Following France, the tour stopped in Sweden, Portugal, Spain, the United Kingdom, Ireland, the Netherlands, Switzerland, Italy, Germany and Poland, having a significant impact on the local economies at each stop.

In Austria, more than 170,000 spectators were expected to attend the shows, bringing in some 100 million euros, according to estimates by the news agency APA.

By the end of the year, “Eras” had already become the first tour to sell more than $1 billion in tickets and it is on track to more than double that by the time it concludes in Vancouver this December.

Austria experienced its first deadly jihadist attack in November 2020, when a convicted IS sympathiser went on a shooting rampage in downtown Vienna, killing four and wounding 23 others before police shot him dead.