Three persons, about whom there are suspicions that they are connected to an Islamist networkwere arrested in Austria, the country’s authorities announced, as security measures around churches and Christmas markets are being stepped up in Vienna and Berlin due to the “increased risk” of a terrorist attack.

The Austrian interior ministry said the initial arrests, made on Saturday, were four. One of the arrested has been released, while the others remain in custody, pending the completion of additional investigations.

Citing “increased risk” police stepped up checks mainly around churches, other places of worship and Vienna’s Christmas markets. Its representative noted, however, that “there is no immediate threat of attack” in the Austrian capital.

On Saturday, Austrian police said in a statement that “terrorists in Europe are calling for committing attacks against Christian events, especially around December 24.

German authorities also announced they had stepped up security around the Cologne cathedral due to what they called an “Islamist threat”. Worshipers who want to attend the Christmas service will go through a strict control at the entrance of the church. “We love all the Christmas traditions and we will not allow ourselves to be intimidated”, Secretary of the Interior Nancy Feser told the Funke Press Group today. “But we take the Islamist terrorist threat very seriously and are very careful,” he added, assuring that the security services are monitoring Islamist circles and acting accordingly, “as shown by the measures being implemented.”

According to the website of German newspaper Bild, security services in Austria, Germany and Spain had indications that an Islamic group wanted to carry out attacks in Europe, possibly on New Year’s Eve or Christmas. The targets may have been religious services in Cologne, Vienna and Madrid.

Bild also reported that a suspect was arrested in Germany. THEThose arrested are reportedly Tajiks who wanted to carry out attacks in his name Islamic State of Khorasan (IS), of an offshoot of the Islamic State in Afghanistan.

No suspicious objects were found during the Saturday night search of Cologne Cathedral.