The teen suspects arrested for plotting an ISIS-style terror attack at one of Taylor Swift’s Austrian concerts this week had planned to drive a bomb-filled car into the crowd to kill as many as possible and had reportedly just been hired by the venue to work security.

Terrifying details of the foiled attack emerged after authorities revealed that two men, ages 19 and 17, had been taken into custody in Vienna on Wednesday — resulting in Swift’s three sold-out Eras shows in the city being canceled.

The two suspects, who investigators say had become radicalized online by ISIS, had allegedly wanted to carry out the attack outside the Ernst Happel Stadium — killing fans with self-made explosives and machetes, security officials said Thursday.

The alleged ringleader, a 19-year-old Austrian with North Macedonian roots, had chemical substances and technical devices stashed inside his home when it was raided by authorities, according to officials.

He had allegedly also made progress in building the bomb he planned to strap to the car, they added.

Meanwhile, the second suspect — a 17-year-old Austrian citizen with Turkish and Croatian roots — was nabbed by special police forces near the stadium where the concerts were supposed to take place this week. 

The second suspect had only just been employed a few days ago by a company providing services at the venue during the concerts, officials said.

Sources told German news outlet Kurier that he’d been hired to work there as security.

The pair had displayed noticeable changes in their behavior in the leadup to their arrests, according to Franz Ruf, public security director at Austria’s Interior Ministry.

The older teen had quit his job on July 25 and told people he had “something big” planned, while the 17-year-old recently broke up with his girlfriend, Ruf said.

The pair had also made contact with others who were apparently aware of the terror plot plans.

A 15-year-old boy was also taken in for questioning Wednesday after the sinister plans were uncovered, though it was unclear if he had been arrested.

Meanwhile, both older suspects had been under surveillance by Austrian authorities and were known risks before their arrests, officials said.

Investigators said they found extensive material related to ISIS and al Qaeda during a raid at the second suspect’s home.

Meanwhile, the main suspect — who authorities say fully confessed to the attack plans after his arrest — had recently sworn allegiance to Islamic State’s leader online, security officials said.

They said the older suspect was “clearly radicalized in the direction of the Islamic State and thinks it is right to kill infidels.”

The names of those allegedly involved haven’t been released due to Austria’s privacy laws.

Swift had been slated to play the three sold-out shows, which were expected to draw 195,000 people, Thursday through Saturday.

It wasn’t immediately clear for which concert the thwarted attack was plotted.

“The situation was serious, the situation is serious. But we can also say: A tragedy was prevented,” Austria’s Interior Minister Gerhard Karner said Thursday.

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

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

News of the terror threat — and subsequent cancellations — devastated “Swifties” across the globe.

Austrian Chancellor Karl Nehammer posted on X 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 wrote, adding that, thanks to intensive cooperation between police and Austrian and foreign intelligence, “the threat could be recognized early on, tackled and a tragedy prevented.”

Austria’s Vice Chancellor Werner Kogler added in a separate post: “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,” Kogler wrote.

Swift hasn’t yet commented publicly about the cancellations or terror threat.

With Post wires