Both suspects in a foiled plot to attack Taylor Swift concerts in Vienna appear to have been inspired by the Islamic State (IS) group and al Qaida, Austrian authorities said on Thursday.

Investigators found bomb-making materials at one of the suspect’s homes, and officials said one of the pair confessed to planning to “kill as many people as possible outside the concert venue”.

Three sold-out concerts on the US singer’s Eras Tour were cancelled on Wednesday because of the plot, devastating Swifties from across the globe.

Many fans had spent thousands of euros on travel and lodging in Austria’s expensive capital city to attend the shows at the Ernst Happel Stadium, which was deserted on Thursday morning, apart from media filming outside.

Officials told reporters that the 19-year-old Austrian suspect began working on his attack plans in July, and only a few weeks ago had uploaded to the internet an oath of allegiance to the current leader of the IS group militia.

He planned to use knives or home-made explosives to carry out the attack outside the stadium.

He was “clearly radicalised in the direction of the Islamic State and thinks it is right to kill infidels,” said Omar Haijawi-Pirchner, the head of the Directorate of State Security and Intelligence.

During a raid on his home in Ternitz, south of Vienna, investigators found chemical substances and technical devices that indicated “concrete preparatory acts”, said Franz Ruf, director-general for public security at the Interior Ministry.

Authorities also found IS and al Qaida material at the home of the second suspect, a 17-year-old Austrian. He was employed a few days ago by a company providing services at the venue for the concerts, and was arrested by special police forces near the stadium.

The suspects’ names were not released in line with Austrian privacy rules.

The three concerts were due to take place at the Ernst Happel stadium in Vienna on Thursday, Friday and Saturday (Heinz-Peter Bader/AP)

No other suspects are being sought, Interior Minister Gerhard Karner said. However, a 15-year-old, who had been in contact with both suspects, was also interrogated by police.

“The situation was serious, the situation is serious. But we can also say a tragedy was prevented,” he said.

Concert organiser Barracuda Music said in an Instagram post late on Wednesday that “we have no choice but to cancel the three scheduled shows for everyone’s safety”.

It cited government officials’ confirmation of a planned attack at the stadium.

Austria’s Vice-Chancellor Werner Kogler wrote on social media platform X, formerly Twitter: “For many, a dream has been shattered today. On three evenings in Vienna, tens of thousands of #Swifties should have celebrated life together.

“I am very sorry that you were denied this. Swifties stick together, hate and terror can’t destroy that.”

The cancellations devastated legions of Swifties who lamented months of now-wasted efforts to make friendship bracelets (Heinz-Peter Bader/AP)

Austrian Chancellor Karl Nehammer posted on X that “the cancellation of the Taylor Swift concerts by the organisers is a bitter disappointment for all fans in Austria”.

“The situation surrounding the apparently planned terror attack in Vienna was very serious,” he wrote.

But he added that, thanks to intensive co-operation between police and Austrian and foreign intelligence, “the threat could be recognised early on, tackled and a tragedy prevented”.

Barracuda Music said “all tickets will be automatically refunded within the next 10 business days”. The same wording was posted under the Vienna dates on Swift’s official website.

The Vienna stadium had been sold out for the planned concerts, APA reported, with an estimated 170,000 fans expected at the Austrian shows. Some who posted on X lamented months of now-wasted efforts to make friendship bracelets and pick out fashionable outfits for the performance.

Swift is expected to perform five concerts at London’s Wembley Stadium between August 15 and 20 to close the European leg of her record-setting Eras Tour.

Members of the public lay floral tributes outside Southport Town Hall in memory of the victims of a stabbing during a Taylor Swift-themed holiday event (Ryan Jenkinson/PA)

The cancellations came just over a week after a stabbing attack in the north-west England seaside town of Southport during a Taylor Swift-themed summer holiday dance and yoga class in which three young girls were killed and 10 others injured. A 17-year-old boy has been charged with murder.

In 2017, an attack at an Ariana Grande concert in Manchester, in northern England, killed 22 people. Suicide bomber Salman Abedi detonated a backpack bomb in Manchester Arena at the end of the show as thousands of young fans were leaving. More than 100 people were injured. Abedi died in the explosion.

An official inquiry reported in 2023 that Britain’s domestic intelligence agency, MI5, did not act swiftly enough on key information and missed a significant opportunity to prevent the bombing, the deadliest extremist attack in the UK in recent years.