Two men were reportedly arrested in Austria on suspicion of terror for allegedly plotting attacks on the upcoming Taylor Swift concerts scheduled in Vienna on Thursday, Friday and Saturday.

A large police operation was conducted early Wednesday in Ternitz, a town of about 15,000 people in the Neunkirchen district of Lower Austria, according to the Austrian daily newspaper Der Standard and The Associated Press.

A man was taken into custody, and special forces conducted a search of his home spanning several hours, police spokesman Johann Baumschlager told the newspaper.

He added that several nearby houses and a section of a retirement home needed to be evacuated, and some roads were closed as a result. Investigators are analyzing several chemical substances seized at the suspect’s home.

Investigators believe one of the suspects had become radicalized online and had sworn an oath of allegiance to the current leader of the Islamic State (ISIS), Der Standard reported.

At a press conference Wednesday evening, General Director of Public Security Franz Ruf, joined by Vienna State Police President Gerhard Pürstl, reportedly confirmed a 19-year-old “Austrian citizen” was arrested in Ternitz in the morning, while a second man was arrested in Vienna in the afternoon.

Kronen Zeitung, another Austrian newspaper, described one of the suspects as an Austrian with North Macedonian roots who lived with his family in Ternitz.