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 the self-proclaimed Islamic State group (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.
What do we know about the alleged plot?
The man had sworn 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 said.
The suspect was planning a lethal assault among the estimated 20,000 Swift 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 alleged plot. The foiled attack was planned for Thursday or Friday, interior minister Gerhard Karner said.
"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."
What was the motivation for the plot?
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 Live Nation urged fans of Coldplay, which is due to play at the same stadium on 21 August, to stay calm, and said it was in contact with authorities. Source: AP / Heinz-Peter Bader
How US intelligence stopped the plot
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.
Karner said foreign intelligence agencies had helped with the investigation, as Austrian law does not allow monitoring of messenger apps.
Fans' reactions
Event organiser Barracuda Music said it had cancelled Swift's three concerts in Vienna, due to start on Thursday for a sold-out audience of 65,000 people 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. Many gathered across Vienna following the cancellations, with many trading bracelets and singing Swift's songs.
"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.
Promoters have said they will refund tickets.
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.
Event organiser Live Nation urged fans of Coldplay, which is due to play at the same stadium on 21 August, to stay calm and, said it was in contact with authorities.
'Swifties' gathered in the streets of Vienna to trade bracelets and sing Taylor Swift songs after the concerts were cancelled. Source: AAP / Heinz-Peter Bader/AP
Swift, 34, has not yet commented on the cancellations on her official Instagram account, which has 283 million followers.
The UK attack
The alleged terror plot was revealed just 11 days after a 17-year-old boy was charged with attacking a Taylor Swift-themed yoga and dance class in the United Kingdom, killing three young girls.
The teenager has been charged with three counts of murder and 10 counts of attempted murder.
Swift responded to the stabbings saying she was "completely in shock" over the "loss of life and innocence and the horrendous trauma inflicted on everyone who was there".
The murders in the UK, fuelled by false rumours that the attacker was a Muslim and an immigrant.
