The trial against a man accused of plotting to attack one of Taylor Swift’s concerts in Vienna nearly two years ago began in Austria on Tuesday.

The plot was thwarted, but Austrian authorities still canceled Swift’s three performances in August 2024. The singer’s fans were devastated, but rallied to turn Vienna into a citywide trading post for friendship bracelets and singalongs.

The defendant, a 21-year-old Austrian citizen known only as Beran A, in line with Austrian privacy rules, faces charges including terrorist offences and membership in a terrorist organisation. He could be sentenced to up to 20 years in prison.

He is on trial alongside a second man, named as Arda K.

Beran A’s lawyer, Anna Mair, said on Monday that her client plans to plead guilty to most of the charges, though she did not specify which ones.

He allegedly planned to target onlookers gathered outside Ernst Happel Stadium – up to 30,000 each night, with another 65,000 inside the venue – with knives or homemade explosives. The suspect hoped to “kill as many people as possible”, authorities said in 2024. The US provided intelligence that fed into the decision to cancel the concerts.

Beran A allegedly networked with other members of Islamic State before the planned attack. Prosecutors say they discussed buying weapons and making bombs, and that the defendant also sought to illegally buy weapons in the days before the performance. In addition, he swore allegiance to the militant group, prosecutors say.

Authorities searched his home on 7 August 2024 and found bomb-making materials. The concerts were scheduled to begin the next day.

“Having our Vienna shows cancelled was devastating,” Swift wrote in a statement posted to Instagram two weeks later. “The reason for the cancellations filled me with a new sense of fear, and a tremendous amount of guilt because so many people had planned on coming to those shows.”

The trial is being held in Wiener Neustadt, about an hour south of Vienna. The proceedings are due to continue until 12 May.

The Vienna plot drew comparisons to a 2017 attack by a suicide bomber at an Ariana Grande concert in Manchester, England, that killed 22 people. The bomb detonated at the end of Grande’s concert as thousands of young fans were leaving, becoming the deadliest extremist attack in the UK in recent years.