Tens of thousands demonstrated in the Turkish capital on Saturday to defend the country's secularist tradition amid simmering tensions over an attempt to ban the Islamist-rooted governing party.
Protesters arrived from various regions carrying Turkish flags and pictures of modern Turkey's founder Mustafa Kemal Ataturk. They chanted: "We will defend the values of the republic."
The protest lasted three hours and finished without incident.
Several demonstrations have been organised across Turkey against the ruling Justice and Development Party (AKP) over the past year. Opponents accuse it of aiming to advance its Islamist ambitions under the guise of improving religious freedoms.
Critics point in particular to the abolition of a ban on the Islamic headscarf in universities and the prohibition of alcohol in restaurants run by AKP municipalities.
The AKP is also currently the subject of a court case seeking to ban the party for allegedly undermining Turkey's secular order in favour of an Islamist regime.
It rejects the charges, saying that it is committed to the separation of state and religion, but argues that a rigid interpretation of secularism in Turkey often violates freedom of conscience.
European Commission chief Jose Manuel Barroso said during a visit to Turkey this week that bridging political rifts is crucial for the country's EU membership bid.
EU Enlargement Commissioner Olli Rehn signalled last month that Turkey's accession talks, which opened in 2005, could be derailed if the AKP is banned.