Clashes have broken out in Rio de Janeiro as striking teachers and their supporters took to the streets to protest against salary levels and a police crackdown on earlier demonstrations.

Organisers rallied thousands in the centre of the Brazilian city on Monday night to demonstrate for the teachers, who are demanding pay increases and an overhaul of the education system. Protesters also spoke out against what many considered to be an excessive use of police force on demonstrating teachers a week ago.

The demonstrators have already rejected the government's proposals of a 15 percent pay rise.

The protest began peacefully, with demonstrators occupying one of Rio's major downtown boulevards. According to police, about 10,000 protesters filled the streets. The teachers' union, however, put that figure at closer to 50,000 people.

The scene turned violent after the marchers reached city hall.

A small group of protesters threw fireworks, grenades, tear gas and set fire to a barricade of rubbish near the public building, where legislation was recently passed changing public teacher's pay and working hours.



The police responded with tear gas to disperse the crowds.



Masked demonstrators also destroyed banks in the surrounding area and later lit a public bus on fire.

Angela Tenorio, a doctor at the demonstration, said unity was necessary.

"I am in support of this unified protest. We have to unify to destroy the corrupt. We don't have politicians, we have thieves, scoundrels, villains!" Tenorio said.

The incident comes one week after a similar teacher demonstration also descended into chaos and clashes.

Al Jazeera's Monica Villamizar, reporting from the site of the clashes in Rio, said that the teachers' protest was part of a wider anti-government movement, which began in June.

"These people belong to a wider social movement known as the "Brazilian Spring" that started in June and criticises President Dilma Rousseff and her policies. They say that the money that Brazil has should not be spent so much in sports events like the World Cup and the Olypmics, but it should be spent on education and public transportation. And they say they're still going to keep on taking to the streets until they see real changes here," she said.

Simone Matias, a public school English teacher at the protest, said the government should focus public sector expenditure on the health and education sectors.

"The country has the money to support or bring Olympiads and the World Cup. Where is the money for education, health and everything else?" she said.

Rio's police forces have come under criticism in recent months for their forceful responses to a series of street protests that have swept the city since June, when small demonstrations against a subway and bus fare hike in Sao Paulo snowballed into a nationwide movement.



The head of the military police was replaced, but allegations of police brutality against demonstrators have persisted under his successor.