The singer’s three Austrian concerts were canceled on Wednesday after two Austrians aged 15 and 17 were arrested for an alleged terrorist plot said to be targeting the events.

Earlier, authorities arrested a 19-year-old Austrian of North Macedonian descent who recently pledged allegiance to the Islamic State (IS) after being radicalized online.

The suspect was reportedly planning a lethal assault among the estimated 20,000 “Swiftie” fans expected to gather outside Vienna’s stadium.

The 19-year-old quit his job less than two weeks before the planned attack claiming he “had big plans,” has made a full confession in custody, according to authorities.

The Iraqi teen, who comes from the same circle as the main suspect, has, apparently sworn allegiance to the Islamic State (IS) jihadist group, but it remains unclear whether he had a direct link to the planned attack, Austrian Interior Minister Gerhard Karner said.

More suspects will be questioned and properties searched as investigators continue to look into the plot, he added.

The American pop star was due to play at Vienna’s Ernst-Happel-Stadion on Thursday, Friday, and Saturday as part of her blockbuster Eras tour, which also brought her to Poland.

Austrian authorities are reported to have received information about the Swift concert threat from U.S. intelligence, as Austrian law does not allow the monitoring of instant messaging apps, which the suspects had used to communicate.

Swift, whose next scheduled performance is in London next week, has not commented on the concert cancellations.

British police have said there is nothing to indicate that the Vienna plot would have any effect on the London show.