RIO DE JANEIRO: Hundreds of thousands of people rallied across Brazil Thursday, as a protest movement over the quality of public services and the high cost of staging the World Cup gathered steam.

The mounting pressure on the government of President Dilma Rousseff in the face of the biggest street protests the South American country has seen in 20 years prompted her to cancel a trip to Japan planned for next week.

Police fired tear gas in Rio de Janeiro, scene of the biggest protest where 300,000 people demonstrated near City Hall, while in the capital Brasilia, security forces blocked protesters trying to break into the foreign ministry.

About 800,000 people marched in rallies across the country of 194 million people, according to an AFP tally -- an intensification of a movement sparked two weeks ago by public anger about a hike in public transport fares.

The protests have spiraled into a wider call for an end to government corruption in the world's seventh largest economy, a call fueled by resentment over the $15 billion cost of hosting the Confederations Cup and the World Cup.

In Rio, police fired tear gas to disperse a small group of stone-throwing protesters. At least one person was injured in the clashes, which sparked panic in the crowd.

"Don't run, don't run," some shouted as they ran through the clouds of tear gas.

Demonstrators meanwhile set ablaze a vehicle owned by the SBT television station.

On Wednesday, protesters had scored a major victory when authorities in Rio and Sao Paulo, Brazil's two biggest cities, canceled the controversial transit fare hikes, but that was not enough to placate the demonstrators.

In Sao Paulo, an estimated 110,000 people flooded the main avenida Paulista to celebrate the fare rollback and keep the pressure on Rousseff's leftist government to increase social spending.

But clashes erupted between a group of ultra-leftists marching behind their red banners and a majority of demonstrators who objected to the presence of political parties.

"This is a social movement, not a political movement. This has nothing to do with ideology," 28-year-old protester Maria Vidal told AFP. "We don't want parties in the demonstration."

One of the leftists was hit in the head by a projectile and blamed a member of the ruling Workers Party. Police were forced to intervene to put an end to the clashes.

Protesters say they want higher funding for education and health and a cut in salaries of public officials. They are also railing against what they viewed as rampant corruption within the political class.

In the capital Brasilia, security forces pushed back demonstrators who tried to break in the foreign ministry and were throwing burning objects, an AFP reporter saw. Military police threw a security cordon around the building.

Some 15,000 people, most of them in their 20s, meanwhile gathered just before dusk on the Alfonso Pena thoroughfare in Belo Horizonte, but a prompt police response of rubber bullets sent them scuttling for cover.

"Brazil, country of corruption," "We want a serious economic policy," "Enough, it's time to speak" and "Brazil is waking up," were just some of the slogans marchers held aloft as they wound their way through the city center.

"I know that in principle staging the Cups is good for Brazil. This should bring development and money. But for decades, the governments we have had have just wasted money," explained Thiago, a 28-year-old medical student.

Thousands more marched in Salvador, the capital of Bahia state, and Recife.

As the protests heated up in the evening, Rousseff's office announced that she would not travel to Japan on June 26-28 as planned for talks with Prime Minister Shinzo Abe.

"She has ultimately decided to postpone this trip, which would have involved several days of travel. She has decided to stay in Brazil due to current events," a source in her office told AFP.

Social media networks have been key to the organization of the mass protests, with demonstrators using the slogan "It's more than just 20 cents" -- a reference to the bus fare hikes -- to rally people to their cause.

The movement has no political coloration and no clearly identified leadership.

Those opposing the hosting of the World Cup are planning a mammoth march to Rio's iconic Maracana stadium on June 30, the day of the Confederations Cup final.

In Belo Horizonte, some marchers predicted the wave of protests could have far-reaching consequences.

"I think they could even bring down the government," said Nancy Borges, a 26-year-old pharmacist. (AFP)

AFP