Vienna authorities have arrested an Iraqi national over an inquiry into an alleged ISIS-inspired plot to attack a concert of international star Taylor Swift in Vienna.

The arrested suspect is aged 18.

Organizers took the extraordinary decision on Thursday to cancel three Swift concerts in Austria after authorities said they foiled a terror attack planned for the Vienna leg of her blockbuster Eras tour, reported CNN.

The Iraqi teenager is the third person to be detained and is believed to have links with the main suspect, a 19-year-old Austrian with North Macedonian roots, the American news channel reported quoting the country's interior ministry.

The ministry claimed both the teens had recently pledged allegiance to the terror group.

“A planned attack on a concert event was successfully thwarted thanks to the timely intervention of the authorities. This success was made possible through extensive investigations that targeted not only the main suspects but also their surrounding network,” it said Friday.

The ministry said authorities are “taking decisive action against anyone who might be involved in terrorist activities or exhibits radical tendencies.”

The Iraqi teenager is “not currently linked directly to the planned attack” but had been arrested under the “broad scope” of the ongoing investigation, it said.

The primary suspects are currently in pre-trial detention.

The 19-year-old suspect quit his job on July 25, saying he had “something big planned” and that he planned to detonate a device within the concert venue, Franz Ruf, Austria’s director general for public security, told CNN.

Explosive devices and detonators were found at the home of the 19-year-old, as well as extensive ISIS propaganda material, 21,000 euros in counterfeit money, machetes, knives and anabolic steroids, Ruf said