Two Austrians have already been arrested. This new detainee has foreign citizenship.

An 18-year-old Iraqi man has been arrested in Vienna on suspicion of links to a group that planned to attack three Taylor Swift concerts in the Austrian capital, which have since been cancelled.

The information is provided by CNN International, which cites a statement from the Austrian Interior Ministry. The man reportedly pledged allegiance to the Islamic State group on August 6, the same day two other suspects — Austrian men aged 19 and 17 — were arrested on charges of making terrorist threats against the American singer's concerts, scheduled for Thursday, Friday and Saturday.

The main suspect, aged 19, was arrested on Wednesday morning in Ternitz, his home, about an hour from Vienna. After searching his home, authorities found a detailed plan for the attacks, which had been organised in close cooperation with another Austrian, aged 17, who was arrested the same day in Vienna.

According to authorities, the main suspect swore allegiance to the Islamic State group in June, after becoming radicalized online. “He is clearly an extremist and believes it is right to kill non-believers,” Omar Hijawi Birchner, director of the government's information and protection service, told a joint news conference on Thursday.

Meanwhile, another 15-year-old Austrian boy was also identified as a suspect and was questioned by authorities, but was eventually released and is helping authorities as a witness to what happened, according to the local newspaper Kurier.

During searches of the main suspect's home, police also found chemicals and devices used to make bombs. The suspect planned to drive a car into the estimated 195,000 people expected to attend the Ernst Happel Stadium. The suspect also considered using knives and axes during the attacks.

The Austrian Director General of Public Security, Franz Ruf, learned that the young man was taking “concrete preparatory measures” for a terrorist attack. According to what Reuters reported from Austrian intelligence, “the plan was to kill people outside the stadium” Ernst Happel.