Chilean police fired tear gas and used water cannons to disperse stone-throwing students protesting against what they call inadequate education reforms and heavy-handed crackdowns on recent demonstrations.
Thousands of students took to the streets of Santiago to condemn President Michelle Bachelet's reforms, claiming they fall short of overhauling an unequal education system inherited from the 1973-1990 dictatorship of late ruler Augusto Pinochet.
The protest began in the early morning hours as students dragged piles of rubbish into the streets and set them on fire, blocking traffic.
Demonstrators then massed outside the education ministry and state television network.
After being dispersed by police, thousands of protesters again took to the streets Thursday night. Hooded protesters gathered around a government building where they erected barricades and attempted to loot shops, police said.
Police reported four officers were hurt in the demonstrations.
"We're still a very long way from achieving our dreams. The reforms are very inadequate," student leader Claudia Arevalo told AFP.
The students, who have been protesting against the education system since 2011, also accused police of using excessive force to break up recent demonstrations.
An art student from Catholic University is currently in critical condition after being knocked to the ground and badly injured by a police water cannon during a protest in the port city of Valparaiso last week.
Police again used water cannons as well as tear gas Thursday as masked protesters attacked them with sticks and stones during an unauthorized march through the center of the capital.
Bachelet won a second term in 2013 with promises to launch an ambitious reform of the education system.
In January, she signed the first reform bill, opening university education to all students and banning for-profit activities at state-funded schools.
Last week, she announced a bill to provide free university education to 60 percent of the poorest students starting next year, reaching 70 percent in 2018 and 100 percent in 2020.
But her reform push has slowed amid a series of damaging corruption scandals, including one involving her son, that have dented her popularity -- currently at 29 percent, her lowest rating ever.