Illustrative: Police officers are seen Ostkreuz Station, in Berlin, Germany. Photo: Reuters/Annegret Hilse.

German police said on Saturday they were heightening security at Cologne Cathedral following indications of an attack planned for New Year’s Eve and in the wake of government warnings in recent weeks about the rising threat of Islamist violence.

The police said in a statement they would use tracker dogs to check the cathedral after evening mass and then close it off. On Sunday, Christmas Eve, they would carry out a security check on all visitors, and recommended they get to services early.

Police said they could not elaborate, citing the ongoing investigation.

German newspaper Bild earlier reported that security authorities in Austria, Germany and Spain had received indications an Islamist group wants to carry out attacks during the Christmas and New Year festivities.

In recent weeks Interior Minister Nancy Faeser has warned of the rising threat of Islamist violence in Germany and elsewhere in Europe as the Israel-Hamas war increases the risk of radicalization.

Austrian police said in a statement they were increasing security on churches and Christmas markets given a heightened state of alert.

“Given that terrorist actors throughout Europe are calling for attacks on Christian events, especially around Dec. 24, the security authorities have taken the corresponding protection measures in public spaces,” the police said.

The Spanish Interior Ministry announced at the beginning of December a reinforcement of security measures from Dec. 18 for the Christmas holidays, with the anti-terrorism alert at level 4 or “high risk,” as it has been since June 2015.