Sao Paulo (AFP) - Brazilian riot police clashed with masked protesters in Sao Paulo and Rio de Janeiro during angry demonstrations against higher transport fares, officials and witnesses said.
A hike in fares was one of the main drivers of the mass demonstrations that roiled Brazil in 2013, in one of the most serious threats to President Dilma Rousseff, who is now under renewed pressure over a badly faltering economy and a billion-dollar corruption scandal.
Friday's protest in Sao Paulo, which drew about 3,000 people, started peacefully and remained so for most of the rally.
But the situation descended into violence when some of the young demonstrators threw stones and lit makeshift barricades made of trash and wood, an AFP photographer said.
Officers responded by firing a noxious gas and using water cannon on the crowds.
But those measures failed to deter the protesters from attacking a bus and vandalizing newsstands and a bank, Sao Paulo military police said on Twitter.
According to authorities, three police officers were wounded in the clashes and 17 protesters were detained for disorderly conduct.
In Sao Paulo the price of a fare on public transport will rise Saturday from 3.50 reais to 3.80 reais ($0.87 to $0.94).
Officials have defended the increase, saying it is below the rate of inflation.
Similar scenes unfolded in Rio, where the hike is slightly steeper.
The rally there was also mostly peaceful until towards the end, when demonstrators clashed with police.
A protest in the city of Belo Horizonte went off peacefully.
The huge demonstrations in 2013, which drew millions to the streets all over the country, began with disquiet over transport fare hikes and escalated into broader protests over corruption and the cost of staging the 2014 football World Cup.