By Sarah Rainsford
BBC News, Istanbul
Thousands of Turks have rallied in Ankara to protest against a government plan to allow women to wear the Islamic headscarf in Turkish universities.
The issue is highly controversial in a mainly Muslim country
The protestors fear such a move would usher in a stricter form of Islam in Turkey, which is a secular state.
Turkey's parliament is expected to approve a constitutional amendment to ease the ban next week.
The ban on the headscarf in higher education was imposed in the 1980s, and has been enforced for the past decade.
A huge crowd gathered at the mausoleum of Ataturk - the man who founded Turkey as a modern, secular republic.
Fearing the gains of his revolution are in danger, the protestors came waving Ataturk's image on banners and carrying the national flag.
The government - which is led by devout Muslims - is pushing a reform that would allow women to wear the religious headscarf to university.
The scarf has been banned outright in private and state universities for almost two decades.
The government argues the ban deprives thousands of women of a higher education.
But Turkey's powerful, secular establishment sees the headscarf as a symbol of political Islam - a threat to their secular way of life, and to the political system here.
Those opposed to the reform include the military, Turkey's judges and university rectors.
They fear it is just the first step to allowing religious symbols into all aspects of public life.
The constitutional amendment is likely to be passed by parliament, where the government has the support of the main nationalist party.
But such is the controversy that the changes are almost certain to be contested in the constitutional court.