A rally organized by Turkey's biggest unions is protesting government policies, which, they feel, are drawing the country closer to a civil war.
The protesters demanded that the government stopped its crackdown in predominantly-Kurdish southern regions, where tight security measures including curfews were imposed.
Ankara deployed up to 10,000 security troops and army soldiers this month in a six-month offensive against militants from the outlawed Kurdistan Workers Party (PKK). Tanks and armored vehicles have been deployed to civilian quarters of major Kurdish-populated cities in southeastern Turkey. Months of heavy street fights have turned residential areas in to piles of rubble.
This year a two-year ceasefire between Ankara and the Kurds was broken in the wake of a series of terrorist attacks on the latter.
An estimated 200,000 people have been forced to leave southern Turkey as a result of the ongoing security operation, according to Turkish media.
On Monday, a similar rally was dispersed by the police, who used water cannons and tear gas against the demonstrators.