Thousands gathered peacefully Saturday at Taksim Square in Istanbul, the Hurriyet Daily News reported.
Police dispersed most of the protesters, though some were moved away with slow-moving water cannon trucks and riot police shields. No water was fired at protesters.
Police arrested 10 people at the protest, which denounced the government's response to the Gezi Park protests from May 28 to June 25, in which 294 children were taken into custody, the newspaper said.
Other protesters gathered in the southeastern province of Diyarbakir's Lice district to condemn the killing of a demonstrator by security forces.
A group of about 250 protesters gathered at Kurtulus Park near Ankara University to denounce the killing of Ethem Sarisuluk, a demonstrator who was shot and killed by police during the Gezi Park protests, Hurriyet Daily News said.
Police used tear gas and water cannons to disperse the Ankara University demonstration, the newspaper said.