Protests in Brazil against bus and underground fare rises have turned violent in the country’s largest city, Sao Paulo, with violence also reported at protests in Rio de Janeiro.
Police fired rubber-coated bullets and tear gas, detaining some 40 people in centre of Sao Paulo.
Police say they seized petrol bombs, knives and drugs.
At least 55 people have been injured in the Sao Paulo clashes, says the Folha de Sao Paulo newspaper.
The newspaper says six of its journalists have been wounded, two of them shot in the face.
Police have been trying to contain the demonstrators.
They have now reached the city’s main avenue, Avenida Paulista, where many shops were vandalised on Tuesday following a bus fare hike protest.
State governor Geraldo Alckmin branded the rioters “vandals” and promised to act to avoid a repeat of the violence.
“The police acted with professionalism,” Mr Alckmin said, rejecting claims that they had used excessive force.
Brazil’s Minister of Justice, Jose Eduardo Cardozo, said the demonstrations were legitimate but resorting to violence and vandalism was unacceptable.
In Rio de Janeiro and other cities, thousands marched to demand that an increase in fares be revoked.
Prices for a single ticket in Sao Paulo were raised on 2 June from 3 reals ($1.40, £0.90) to 3.20 reals ($1.50, £0.96).
The authorities say that the rise is well below inflation, which since the last price rise in January 2011 has been at 15,5% according to official figures.