An Austrian man arrested over an alleged plot to strike a Taylor Swift concert in Vienna planned to carry out a suicide attack that would have caused a "bloodbath" and had vowed loyalty to Islamic State (IS), authorities said.
The 19-year-old man made a full confession in custody, Austria's general director for public security Franz Ruf told a news conference on Thursday.
He swore allegiance to the IS group's leader on the internet and had chemicals, machetes and technical devices at his home in the town of Ternitz in preparation for an attack, Ruf added.
The suspect was planning a lethal assault among the estimated 20,000 'Swiftie' fans set to gather outside Vienna's Ernst Happel Stadium, said national intelligence head Omar Haijawi-Pirchner. Two other Austrian youths aged 17 and 15 were detained on Wednesday over the reported plot.
"The main perpetrator has confessed that he was supposed to carry out a suicide attack with two accomplices," Austrian Chancellor Karl Nehammer said.
"The suspects actually had very specific and detailed plans ... to leave a bloodbath in their wake."
Authorities painted a picture of the main suspect having self-radicalised, transforming his appearance and sharing Islamist propaganda online. He quit his job on 25 July, telling people he had "big plans", Ruf said.
The 17-year-old suspect had been given a job with a company a few days ago that was providing services at the stadium, according to security officials.
Event organiser Barracuda Music said it had cancelled Swift's three concerts in Vienna, due to start on Thursday for a sold-out 65,000 audience each, in coordination with the singer's management team.
Fans, many of whom had travelled a long way to Vienna, expressed both dismay and understanding.
"It's just heartbreaking, just frustrating. But at the end of the day I guess it's for everyone's safety," said Mark del Rosario, who had flown from the Philippines to see the wildly popular US singer.
Taylor Swift performed to more than 600,000 fans in seven sold-out shows during the Australian leg of her Eras tour. Source: AAP / DEAN LEWINS/AAPIMAGE
US broadcaster ABC cited law enforcement and intelligence sources as saying Austrian authorities had received information about the Swift concert threat from US intelligence.
It quoted the sources as saying that at least one of the suspects had pledged allegiance to ISIS-K, a resurgent wing of IS, on Telegram in June, though the plot was IS-inspired rather than directed by the group's operatives.
Austrian Interior Minister Gerhard Karner said foreign intelligence agencies had helped with the investigation, as Austrian law does not allow monitoring of messenger apps.
British police said on Thursday there was nothing to indicate that the planned attack in Vienna would have an impact on Swift's shows at Wembley Stadium in London next week.
This week's shows were to be part of the record-breaking Eras Tour by American singer-songwriter Swift which started in March 2023 and is set to conclude in December.
Swift, 34, has not yet commented on the cancellations on her official Instagram account, which has 283 million followers.
Her fans were horrified at the threat, with some begging organisers to postpone the concert instead of cancelling it outright. Promoters have said they will pay back tickets.
