Hundreds gathered outside Sweden's consulate in Istanbul on Saturday to protest the Koran burning outside the Turkish embassy.
Earlier in the day, the Danish-Swedish politician Rasmus Paludan burned the Koran outside the Turkish embassy in Stockholm.
"It is unacceptable"
It led to protests both outside the Swedish consulate in Istanbul and outside the embassy in the capital Ankara.
The Swedish flag was burned and a black wreath with the message "stop Islamophobia" was hung up.
- It is unacceptable that the Swedish authorities allow such a provocation, which will make many Muslims around the world angry, outside an embassy.
It is also not a coincidence that it was right outside the Turkish embassy, says protester Mesut Emre Balci.
Claims from Turkey
Fahrettin Altun, politician and close associate of Turkish President Erdogan, writes on Twitter that Sweden cannot hide behind freedom of expression.
"If the Swedish authorities take their nation's security seriously and want to join NATO, they also need to care about their potential NATO ally".
Turkish Foreign Minister Mevlüt Cavusoglu also demanded that the Koran burning be stopped.
Billström: "Scary"
Foreign Minister Tobias Billström (M) has expressed the government's disassociation from Paludan's action on Twitter:
"Islamophobic provocations are terrifying.
Sweden has far-reaching freedom of speech, but that does not mean that the Swedish government, or myself, support the views expressed".