VIENNA, AUSTRIA — 

The 19-year-old Austrian who masterminded a foiled plot to attack Taylor Swift fans at a concert in Vienna with a bomb or knife had pledged allegiance to the Islamic State militant group, authorities said on Thursday.

The main suspect, 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 loyalty to the IS militant group's leader on the internet and kept chemicals and technical devices at his home in the town of Ternitz in preparation for an attack, Ruf said.

The 19-year-old, whose name was not given, was planning an attack with an explosive or knife among the estimated 20,000 "Swiftie" fans set to gather outside the stadium, said national intelligence head Omar Haijawi-Pirchner.

"There is currently no information that other concerts are subject to an explicit threat," he said at the news conference.

Two other Austrian youths, ages 17 and 15, were also detained Wednesday over the foiled plot.

Swift's three concerts in Vienna, due to start on Thursday for a sold-out audience of 65,000 each, were canceled, to the consternation of fans, many of whom had traveled 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 for the show.

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, although the plot was IS-inspired rather than directed by the group's operatives.

Austrian Interior Minister Gerhard Karner said foreign intelligence agencies helped with the investigation, as Austrian law does not allow monitoring of messenger apps.

Event organizer Live Nation urged fans of Coldplay, which is due to play at the same stadium on August 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 her shows at Wembley Stadium in London next week.

Past attacks and plots

"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 planned attack also recalled a foiled plot by three IS-linked suspects against Vienna's gay pride parade last year.

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

Swifties disappointed

The 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, 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 canceling it outright. Promoters have said they will pay back tickets.

"I can’t believe the concert i’ve been waiting for over 10 years is now gone. I don’t think i’ll ever get over this," wrote one fan on social media.

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

Some who had traveled from abroad for the concerts planned to do some sightseeing or hang with friends instead.

"We'll check out some museums, maybe catch up with a few friends who reside here," said del Rosario. "But apart from that, maybe look at Swiftie-organized events. To be with fellow fans, you know, share the same pain and just dance it out. As I believe Taylor Swift would want us to have fun."

One group of local Swifties said they had received permission to still hold tour parties in coordination with local police.