An Austrian teenager arrested over an alleged plot to strike a Taylor Swift concert in Vienna had built explosive devices for his attack and had pledged loyalty to Islamic State, authorities said on Thursday.

The 19-year-old man, who has North Macedonian roots, made a full confession in custody, Austria’s general director for public security Franz Ruf told a news conference.

He swore allegiance to the IS group, opens new tab’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, whose name was not given, was planning a lethal assault among the estimated 20,000 “Swiftie” fans set to gather outside Ernst Happel Stadium, said national intelligence head Omar Haijawi-Pirchner.

“He wanted to carry out an attack in the area outside the stadium, killing as many people as possible using the knives or even using the explosive devices he had made,” he said, adding there were no explicit threats to other concerts.

Two other Austrian youths aged 17 and 15 were also detained on Wednesday over the foiled plot. Authorities painted a picture of the main suspect as having self-radicalised, transforming his appearance and sharing Islamist propaganda online. He quit his job on July 25, telling people he had "big plans", Ruf said.

One neighbour told Austrian broadcaster Puls24 that he kept himself to himself and had grown a “Taliban beard”.

Swift’s three concerts in Vienna, due to start on Thursday for a soldout 65,000 audience each, were cancelled, to the consternation of fans, many of whom had travelled far.

“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 U.S. singer.

MUSIC WORLD ROCKED

U.S. broadcaster ABC cited law enforcement and intelligence sources as saying Austrian authorities had received information about the Swift concert threat from U.S. intelligence.

It cited the sources as saying 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.

Event organiser Live Nation urged fans of Coldplay, which is due to play at the same stadium on Aug. 21, to stay calm and said it was in contact with authorities.

It did not comment on whether the show would take place.

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.

“Concerts are often a preferred target of Islamist attackers, large concerts,” said Karner, listing the 2015 attack on Paris' Bataclan venue and the 2017 bombing at the Manchester Arena where U.S. pop star Ariana Grande had played.

The plot in Austria also brought to mind a foiled plan by three IS-linked suspects against Vienna's gay pride parade last year. IS was largely crushed by a U.S.-led coalition several years ago after establishing a “caliphate” in large areas of Iraq and Syria, but has still managed some major attacks while seeking to rebuild and reinvent itself.

NATIONAL SECURITY REVAMP

Austrian authorities have revamped their national security intelligence in the wake of a 2020 attack by a convicted jihadist in the centre of Vienna that left four dead, the first such militant attack in the Austrian capital in a generation.

This week's shows were to be part of the record-breaking Eras Tour by the American singer-songwriter which started on March 17, 2023, in Glendale, Arizona, U.S., and is set to conclude on Dec. 8, 2024, in Vancouver, Canada.

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 organizers to postpone the concert instead of cancelling it outright. Promoters have said they will pay back tickets.

“As disappointing as not being able to go to this concert is TRUST ME u do not want to experience that,” added another.