The main suspect arrested for plotting a terror attack at a Taylor Swift concert in Vienna has confessed to planning to drive a car into a crowd of ticketless fans outside the arena and attack them with machetes.

The 19-year-old Austrian citizen had recently sworn an oath of allegiance to the Islamic State online and had allegedly reached the advanced stages of constructing a bomb.

Omar Haijawi-Pirchner, head of the State Security and Intelligence Directorate in the Federal Ministry of the Interior said the older suspect wanted “to kill himself and a large crowd either today or tomorrow”.

He was “clearly radicalised in the direction of the Islamic State and thinks it is right to kill infidels”, Mr Haijawi-Pirchner added.

Another young terror suspect, 17, was arrested on Wednesday, and police also questioned a 15-year-old. Both cases were connected to the planned deadly attack at the Ernst Happel Stadium.

The second suspect, who has Turkish and Croatian roots, had started a job at the concert venue days before the event was cancelled over the terror threat, officials said.

Swift was set to perform three sold-out shows to over 150,000 people across Thursday, Friday and Saturday for the international leg of the Eras Tour. Her fans often gather outside venues hoping to score a last-minute ticket or just to listen to the show.

“With confirmation from government officials of a planned terrorist attack at Ernst Happel Stadium, we have no choice but to cancel the three scheduled shows for everyone’s safety,” Barracuda Music, the event’s organiser, said on Wednesday evening.

Investigators have since revealed the 19-year-old suspect stole chemicals to build a bomb to murder spectators.

Police cordoned off and partially evacuated the area around the suspect’s house in Ternitz, a small town at the scenic foot of the Alps in Lower Austria. Around 100 people, including residents of a retirement home, had to be evacuated.

Chemical substances were found at home, which the suspect had stolen from his former workplace, a metalworking company, Franz Ruf, the public security director at Austria’s Interior Ministry, said.

Local authorities are said to have acted after receiving a tip-off from another country’s intelligence services about a suspected terror cell. CBS News reported it came from the US Secret Service.

The suspect had recently declared his allegiance to an Afghanistan-based splinter cell of IS, known as “Khorasan Province” (ISKP), according to Austria’s broadcaster Oe24.

The terrorist outfit is responsible for the massacre at a concert hall in Moscow in March, which killed some 150 people, and for launching threats to attack stadiums in Dortmund, Munich and Berlin during the Euros.

Investigators said they also found extensive material related to the Islamic State group and al-Qaida at the home of the second suspect.

Karl Nehammer, the Austrian chancellor, said in a statement on Wednesday, that “the cancellation of the Taylor Swift concerts by the organizers is a bitter disappointment for all fans in Austria.”

“The situation surrounding the apparently planned terror attack in Vienna was very serious,” he said. But he added that thanks to intensive cooperation between police and Austrian and foreign intelligence, “the threat could be recognized early on, tackled and a tragedy prevented.”

‘IS riff-raff in our country’

Austria’s interior minister has criticised the fact the country had to rely on foreign intelligence to foil the terror plot.

“We are dependent on foreign intelligence services because we do not have the legal means to monitor messenger services on which potential offenders communicate today,” Gerhard Karner, said.

“We don’t want or need mass surveillance, but rather modern tools for the police so that they can do their job for the safety of the population.”

Dominik Nepp, the leader of the far-right Freedom Party (FPÖ) in Vienna, seized the moment to criticise the government’s immigration policies.

“Taylor Swift can play all over the world, but not here! Vienna is really different! My daughters and I have been looking forward to this for a year!” he wrote on social media.

“Only because we have this IS riff-raff in our country thanks to the uncontrolled welcome culture!”