Austrian, German, and Spanish police were on high alert at cathedrals in several cities due to concerns that Islamists were planning a terrorist attack on Christmas or New Year's Eve, with several suspects already arrested in Vienna and Germany, according to German reports.
According to the Bild, several suspects were arrested in the Ottakring district of Vienna, while another was arrested in Saarland, Germany.
The arrested suspects are Tajiks allegedly affiliated with the Islamic State in Khorasan Province, the branch of ISIS in south-central Asia, according to the report.
Vienna Police noted in a press release that there is an "increased terror alert level" and "generally an increased risk in Austria during the Christmas holidays."
"Since terrorist actors across Europe are calling for attacks on Christian events – especially around [Christmas Eve,] December 24 – the security authorities have increased the corresponding protective measures in public spaces in Vienna and the federal states," Vienna Police said, adding that there would be increased patrols and surveillance during the holidays, with attention focused primarily on churches, religious events, and Christmas markets.
According to Bild, St. Stephen's Cathedral is particularly at risk due to the threat.
Police heighten security at Cologne Cathedral
In Cologne in western Germany, the Cologne Cathedral was searched on Saturday evening, with police looking for explosives and other dangers in the area, according to the German, best-selling European newspaper.
The Cologne Police said in a press statement that police were taking "special protective measures" beginning on Saturday evening, adding that "the police will not comment on details of the available findings due to ongoing investigations by the police state security agency."
Chief of Cologne Police Michael Esser stated: "We will take everything into account this evening to ensure the safety of cathedral visitors on Christmas Eve. In coordination with the security officer of the cathedral chapter, the cathedral is searched with sniffer dogs after the evening mass and then locked. Tomorrow all visitors will be screened before entering the church."