After a Catholic religious sister was attacked on a bus, police have arrested a 19-year-old Afghan, according to police in the Austrian state of Styria. The attack came among a spate of anti-Catholic attacks and demonstrations in Austria.

The nun, 76, was attacked on Saturday afternoon on a bus in the Austrian city of Graz. The perpetrator hit the sister in the face and then fled.

Police officers seized video material from the bus, after which the State Office for the Protection of the Constitution and Counter Terrorism arrested the Afghan-born teenager. The suspect, already known to the police for drug offenses and assault, has confessed to the crime; his motive is still unclear, police say.

Several anti-Christian incidents have caused a stir in Austria, after last week's terrorist attack by a man shouting Islamist phrases at a cathedral in France.

Between 30 and 50 young people also attacked a church in Vienna-Favoriten on Thursday evening. According to several media reports, the perpetrators were a group of young Turks. The attackers stormed into the parish church of St. Anton in Favoriten, shouted "Allahu Akbar," and kicking pews and other furnishing in the church. 

The Archdiocese of Vienna condemned the attack and called for "quick clarification" and "consequences."

The Vienna State Office for the Protection of the Constitution and Combating Terrorism was given video material by the church's deputy pastor, which is currently being evaluated.

Another Afghan was arrested over the weekend while shouting "Islamic slogans" in St. Stephen's Cathedral, Vienna police confirmed to CNA Deutsch, CNA's German language news partner.

Churches in Vienna are now being monitored more closely as part of the patrol service, the police told CNA Deutsch.

A version of this report was first published by CNA Deutsch. It has been translated and adapted by CNA.