Austria and Turkey accused each other on Monday of responding inappropriately to clashes between Kurdish and Turkish protesters in Vienna last week, further straining already tense relations.
The violence began on Wednesday, when a brawl broke out after Turks heckled a Kurdish gathering in Vienna, police said. Kurdish protests on Thursday and Friday with around 300 people, according to a police count, then led to clashes with Turkish counter-protesters in which stones and fireworks were thrown.
Such violence is rare in Vienna, which has a large ethnic Turkish minority. Austria's conservative Chancellor Sebastian Kurz is a vocal critic of Turkish President Tayyip Erdogan, and their governments traded barbs over the violence.
"Foreign Minister Alexander Schallenberg expressed to the Turkish ambassador the clear expectation that he contribute to de-escalation rather than pouring fuel on the fire," Austria's Foreign Ministry said after summoning the ambassador.
Earlier on Monday Turkey's Foreign Ministry strongly criticised Austria's handling of the protests, which it said were by groups linked to militants of the outlawed Kurdistan Workers Party (PKK).
"Austria's ambassador to Ankara will be invited to our ministry and informed of our concern," it said, accusing Austrian security forces of meting out "harsh" treatment to the Turkish protesters.
Austria said police intervention had prevented worse violence and pledged to find out who was behind the clashes. The police made 11 arrests and seven officers were injured in the clashes, the Interior Ministry said.
"Describing demonstrators as supporters of terror organisations is something we reject. The minister urgently requested that such statements be avoided in future," Austria's Foreign Ministry said, defending the right to peaceful protest.
PKK militants have been waging an insurgency against the Turkish state since 1984 in a conflict that has claimed more than 40,000 lives. The PKK is designated a terrorist group by Turkey, the European Union and the United States.