Police in Istanbul have clashed with Turkish right-wing demonstrators protesting against what they describe as concessions to Orthodox Christians.
Protesters burned an effigy of the patriarch
Turkish media said the police used tear gas and batons to disperse hundreds of protesters marching towards the offices of Ecumenical Patriarch Bartholomew I.
Earlier on Sunday, the crowd burned his effigy and threw stones at police.
Some nationalists have been angered by the government's decision to allow the reopening of an Orthodox seminary.
The Istanbul seminary, closed by the Turkish authorities in 1971, trained generations of church leaders, including Bartholomew.
The BBC's James Ingham says reforms allowing more rights to Orthodox Christians are promoted by a government keen to show it is committed to a secular society as its possible membership of the European Union is being considered.
The EU's commissioner for enlargement, Guenter Verheugen, is beginning a four-day visit to Turkey, to assess whether the country is ready to start entry talks.
The EU has said it is keen to see wider religious freedom ahead of membership talks.
Christians are a minority in Turkey, but Istanbul remains the seat of the Ecumenical Patriarch - who is considered to be the spiritual leader of all Orthodox Christians.
But Nationalist leader Yuksel Kaleci said in a statement that Turkey "is making concession after concession to foreigners and especially to the Patriarchate".
The Patriarchate condemned the "violence" by demonstrators on Sunday.
In a statement, it said the protests were the result of "the provocations of people
intent on blocking Turkey's EU path".