Protesters hurling petrol bombs have clashed with riot police in Brazil at the Confederations Cup football match, overshadowing the host nation's victory over world champions Spain in the final.

A fiesta of football inside Rio's iconic Maracana Stadium saw Brazil triumph 3-0 over Spain on Sunday, to seal their third title in a row, but the last day of the tournament saw no let-up in the protests that have taken place throughout the event.

More than a million Brazilians had taken to the streets during the tournament, venting anger at the estimated $15bn being spent on the Confederations Cup and World Cup in 2014 while bemoaning the South American country's public services.

Brazilian President Dilma Rousseff - who was booed when she appeared alongside FIFA President Sepp Blatter at the opening game in Brasilia two weeks ago - declined to attend Sunday's game.

Instead Rousseff, whose popularity has plunged since the start of the unrest, issued a congratulatory message to the victorious Brazilian team.

"In this memorable campaign, our athletes showed joy, creativity, team spirit and unity which conquered all Brazilians and they offered the world a great spectacle," Rousseff.

"Today I joined all Brazilians in celebrating this great victory."

Before kick-off outside the stadium a small group of hooded protesters, some armed with screwdrivers and slingshots, lit a fire in the street and hurled stones at police who responded by firing tear gas and rubber bullets as helicopters circled overhead.

"Unfortunately, the incidents were started by protesters who hurled makeshift bombs and stones at police," Henrique Guelber, of the Center for the Defense of Human Rights, told the G1 news website.

More than 11,000 police and troops were mobilised to ensure security for 78,000 fans at the Maracana as protests continued.

"We are against the privatisation of the stadium and forced housing displacement, linked to the 2014 World Cup and the [2016 Rio summer] Olympics," said Renato Cosentino, a spokesman for one of the groups sponsoring Sunday's protest.

Al Jazeera's Adam Raney, reporting from Rio de Janeiro, said that protests were likely to continue, though it was unclear what the protesters would direct their energy at with the football tournament wrapped up.