Student protests in Athens over planned reforms to secondary education led to clashes with the police and a blockade near the central Syntagma Square on Monday.
Scores of protesters threw stones and launched Molotov cocktails towards police officers, who responded with tear gas.
Images released via epa showed a protester hurling a fire extinguisher in front of a group of riot police.
The clashes then moved towards the Temple of Olympian Zeus, where students set fire to a container and other items near the Arch of Hadrian, an area of the Greek capital that is popular with tourists.
Students from various schools joined the action over changes in the pipeline under the government of Prime Minister Alexis Tsipras, which would affect the last years of secondary education as well as access to university.
The reforms would lead to more national exams and favor private schools that offer courses to prepare for university entrance exams, according to protesters.
Students also denounced a lack of teaching staff and the doing away with specialisms in technical colleges.