Demonstrators protesting against São Paulo bus fares vandalised turnstiles and ATMs and set buses on fire at the city's main station, after a peaceful protest turned violent.
The protests, organised by the group Movimento Passe Livre (Free Pass Movement) gathered outside the city's municipal theatre and marched to the bus station on Friday night.
At least one police officer was injured in the ensuing clashes, which saw activists setting off fire extinguishers and spray painting slogans on the terminal.
Al Jazeera's Gabriel Elizondo, reporting from São Paulo, said demonstrators were calling for better public transport and a drop to zero of all the bus fares in the city.
Movimento Passe Livre has been demonstrating against São Paulo bus fares since 2004, but the protests have grown since June, when a wave of demonstrations against the high cost of living spread around Brazil during the Confederations Cup.
"As long as transportation is managed according to the interests of businessman and not those of the public who uses it on a daily basis, we will remain on the streets fighting," said protester Marcelo Hotimsky.
Meanwhile, Brazilian President Dilma Rousseff said on Friday that São Paulo will receive the equivalent of $2.5bn of federal funds to expand its subway and commuter train networks.
The funds are part of the $9.6bn the federal government will lend São Paulo state to improve its urban mobility. The city will have 30 years to repay the government at subsidised interest rate.