“We will look very precisely at who was behind this escalation during these recent demonstrations,” Reuters cited Interior Minister Karl Nehammer as saying on Monday. “It is completely unacceptable for Turkish conflicts to be carried out on Austrian territory.”

Meanwhile, the Turkish Foreign Ministry said Kurdish protesters involved in the clashes had ties to terrorist groups, and accused Austrian authorities of turning a blind eye to terrorist propaganda.

“The rallies which were organized by the PKK-terrorist organization and its supporters in Vienna in recent days have been a new manifestation of insincerity in the fight against terrorism,” the ministry statement said.

Turkey said it would also summon Austria's ambassador.

“The Ambassador of Austria to Ankara will be summoned to the Ministry in order to share our concerns,” the ministry said, saying the outlawed Kurdistan Worker’s Party (PKK) members and sympathizers had been “allowed to organize rallies four days in a row,” while Austrian security forces “used violence against the Turkish youth.”

The clashes occurred as Turkish nationalists attacked Kurdish rallies last week, Associated Press reported. Stones and firecrackers were thrown in the subsequent skirmish.

Some people in the group were using a hand gesture used by the Grey Wolves, an ultranationalist militant group affiliated with Turkey’s far-right Nationalist Movement Party (MHP), according to Austrian police, Ahval news agency reported.

Austria had added the hand signal to its list of banned symbols in 2018.

“It would be unacceptable if it turns out that Turkish groups on Ankara’s orders, so to speak, are causing destabilization in Austria,” Nehammer said.

Journalist Jake Hanrahan said the Grey Wolves members had knives on them, and that there was video evidence of them setting a building on fire.

Reporter’s code: 50101