Turkish riot police fired rubber bullets and tear gas on Friday on students demonstrating against President Recep Tayyip Erdogan and government control of universities.
Brawls erupted between police wearing helmets and riot shields and some of the some 200 protesting students at an Istanbul University campus.
Some of the students were injured and police made a number of arrests, an AFP photographer said.
The students were demanding the abolition of the Higher Education Board (YOK) which was created by the then military junta in 1981 to manage universities and is regarded as an instrument of state control.
"The youth will not be intimidated, Erdogan and YOK will be toppled," said one banner brandished by the protesters.
"The killer government will be brought to account," they shouted.
Police also used water cannon against a smaller demonstration denouncing the education board in the Mediterranean resort of Antalya, where the G20 summit of world leaders is taking place next week, media reports said.
The unrest erupted just days after Erdogan's Justice and Development Party (AKP) decisive victory in Sunday's election.
In 2013, his government was shaken by massive nationwide demonstrations that grew out of a small protest about plans to develop a park near Istanbul's Taksim Square.