Two men were arrested on August 7 amid a major police operation in Austria.

One man described as a "19-year-old Austrian citizen" by the country's Director General for Public Security, Franz Ruf, was arrested in the early hours of Wednesday in the town of Ternitz and is suspected of taking concrete preparatory action for a terrorist attack. 

The operation in the town, located in the Neunkirchen district of Lower Austria and home to fewer than 15,000 people, prompted the evacuation of several houses and the closure of streets, according to police spokesman Johann Baumschlager.

A search of the suspect's residence, which lasted for many hours, was also carried out, and resulted in the seizing of chemical substances, according to Austrian news outlet Kronen. 

The suspect had allegedly focused his attention on a series of Taylor Swift concerts, completely sold out, scheduled to take place at the Ernst Happel Stadium in Vienna between August 8 and 10.

Mr Ruf said: "The suspected perpetrator was focused on the Taylor Swift concerts. Preparatory actions were detected."

A second man was arrested in Vienna on Wednesday afternoon. 

One of those arrested is believed to have become radicalised on the internet and to have sworn allegiance to the current leader of the Islamic State, Austrian daily Der Standard wrote.

The Taylor Swift concerts due to take place have now been cancelled.