Police clashed with hundreds of rock-throwing nationalist Turks who staged a protest outside the seat of the spiritual leader of the world's Orthodox Christians.
The protesters on Sunday burned an effigy of Ecumenical Patriarch Bartholomew I, whom far-right groups accuse of working against Turkish interests.
The demonstrators ignored calls to disperse, broke paving stones and hurled them at police, Anatolia news agency reported.
Police used tear gas against the demonstrators. Officers pursued some protesters down side streets, television station NTV said.
It was not immediately clear if anyone was injured in Sunday's scuffles, but NTV said some cars in the area were damaged.
The group staged the demonstration to call on the Ecumenical Patriarchate to reopen a gate that has remained shut for more than 180 years out of respect for Patriarch Gregory V, who was accused of conspiring against the Ottoman Empire and was hanged from it in 1821.
The nationalists see the Patriarchate's refusal to reopen the gate, which is the main entrance to the complex, as a sign of its "anti-Turkish" sentiment. Nationalist groups have dubbed the entrance "the gate of hatred."
The patriarchate says the gate was welded shut and cannot be reopened.
"Turkey is making concession after concession to foreigners and especially to the Patriarchate," Yuksel Kaleci, a nationalist leader, read from a statement before the clashes erupted, according to Anatolia.
The protest came as the Patriarchate seeks to reopen an Orthodox seminary that Turkish authorities closed in 1971. The seminary trained generations of church leaders, including Bartholomew, and is seen as crucial for the education of future leaders.
Members of Turkey's government, have expressed support for the proposal, which nationalists strongly oppose.
The government is seeking Turkish membership in the European Union. The 25-member group has made expanding religious freedoms one of its conditions for starting membership talks.
The Patriarchate condemned the "senseless violence" outside the complex. In a statement Sunday, it said the protests were the result of "the provocations of people intent on blocking Turkey's EU path."
Bartholomew has spiritual authority over the world's 300 million Orthodox Christians and directly controls several Greek Orthodox churches around the world, including the Greek Orthodox Archdiocese of America.
Turkey only recognizes the patriarch as the religious head of the Greek community in Turkey.
Although few Greek Orthodox Christians remain in overwhelmingly Muslim Turkey, the Patriarchate is still based in Constantinople.
It dates from the Orthodox Greek Byzantine Empire, which collapsed when the Muslim Ottoman Turks conquered the city in 1453. Istanbul, then called Constantinople, was the capital of the Byzantine Empire.