Thousands of people demonstrated in central Ankara on Saturday in protest at a widening investigation into an alleged coup plot, seen by critics as a crackdown on the government's opponents.
The protests took place at the mausoleum of the founder of modern Turkey, Mustafa Kemal Ataturk, after a wave of detentions in the investigation continued this week, to include a university head and an anti-government media executive.
The case has shaken markets in the European Union candidate country and heightened tensions between the government and the country's traditionally powerful military.
Nearly 150 people, including retired senior military officers, lawyers and academics, are on trial for alleged links to a shadowy right-wing group known as Ergenekon, accused of trying to topple Prime Minister Tayyip Erdogan's AK Party.
Prosecutors say the group was planning a campaign of bombings and attacks to force the army to step in. The Turkish military has pushed four elected government out of power since the creation of the modern state, most recently in 1997.
Protesters waved flags and shouted slogans. Some said the case was part of the struggle between the Islamist-rooted AK Party and the secularists whose long grip on power came to an end when the AK Party won elections in 2002.
"I am worrying about the course of Turkey now. Unfortunately the ones running Turkey these days seem to be against the secularism of the Turkish republic," said Perihan Yinanc.
Some protesters chanted: "The government must resign."
The government has defended the investigation and has said the judiciary is impartial. The army denies links to Ergenekon.
The two main opposition parties, the People's Republican Party and the Nationalist Movement Party, have accused the government of abusing the law for political gains.
Reuters