Protesters burn the national flag of Sweden as they demonstrate in front of the Consulate General of Sweden in Istanbul, Turkey, Jan. 21, after Rasmus Paludan, leader of the Danish far-right political party Hard Line and who also has Swedish citizenship burned a copy of the Koran near the Turkish Embassy in Stockholm. Reuters-Yonhap

Outrage over a Quran-burning protest in Sweden produced a second day of protests in Turkey, reflecting tensions between the two countries.

Some 250 people gathered outside the Swedish Consulate in Istanbul, where a photo of Danish anti-Islam activist Rasmus Paludan was set on fire. Paludan burned Islam's holy book outside the Turkish Embassy in Stockholm, Saturday, sparking protests in Istanbul and Ankara that night.

Participants in Sunday's event carried green flags featuring the Islamic proclamation of faith and banner that said, ''We condemn Sweden's state-supported Islamophobia.'' A sign on a window of the Swedish Consulate read, ''We do not share that book-burning idiot's view.''

The protests have renewed concerns about Turkey holding up Sweden and Finland's bid to join NATO. Turkey has not yet ratified the Nordic nations' memberships in the military alliance, saying Sweden needs to address Ankara's security concerns.

Turkish officials slammed Sweden for allowing the Quran-burning protest but President Recep Tayyip Erdogan did not comment on it during his weekend speeches.

Swedish Prime Minister Ulf Kristersson tweeted late Saturday that freedom of expression was crucial to democracy but added that ''what is legal is not necessarily appropriate.''

''Burning books that are holy to many is a deeply disrespectful act. I want to express my sympathy for all Muslims who are offended by what has happened in Stockholm today,'' Kristersson said.

Mustafa Demircan, one of the people protesting in Istanbul on Sunday, said the act of burning the Quran should not be considered an act protected by the right of free expression.

Protesters also gathered outside the Swedish Embassy in Ankara for a second day. In southeastern Sanliurfa Province, men held the Quran high after prayers in a mosque and chanted ''God is great'' in videos shared online. More protests were planned for Sunday evening. (AP)