Hundreds of thousands of people have rallied across Brazil as part of a protest movement over the quality of public services and the high cost of staging the World Cup.

President Dilma Rousseff called for an emergency cabinet meeting on Friday amid mounting pressure on her government in the face of the biggest street protests the South American country has seen in 20 years

The demonstrations have also prompted her to cancel a trip to Japan planned for next week.

Local media reported that 1.2 million people took part in rallies across the country of 194 million people - an intensification of the movement which started two weeks ago to protest at bus fare increases.

Police fired tear gas in Rio de Janeiro, scene of the biggest protest where 300,000 people demonstrated near City Hall, to disperse stone-throwing protesters. At least one person was injured in the clashes. Demonstrators also set ablaze a vehicle owned by the SBT television station.

On Friday, CBN radio and the website of the Estado de Sao Paulo newspaper, both respected, mainstream media carried reports speculating on the suspension of the Confederations Cup, an eight-nation football tournament considered a dry run for next year's World Cup.

Violence in Brasilia

In the capital Brasilia, security forces including military police blocked protesters trying to break into the foreign ministry building and throwing burning objects.

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.

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.

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

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

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

About 15,000 people, most of them in their 20s, gathered just before dusk on Thursday 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 centre.

Recife and Salvador rallies

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

Al Jazeera's Gabriel Elizondo, reporting from Sao Paulo, said police in Recife said marches there attracted more than 100,000 people, while a small protest in the northeastern city of Salvador resulted in clashes between police and protesters.

Many marching against corruption and the cost of the 2014 World Cup are also angry at the media, including the influential Globo network, accused of belittling their movement.

In Sao Paulo, Globo TV crews have been jeered while covering protest rallies and on Tuesday demonstrators set the satellite van of another station ablaze.

Social media networks have been key to the organisation of the mass protests, with demonstrators using the slogan "It's more than just 20 cents" - a reference to the bus fare rises - to rally people to their cause. The movement has no political hue and no clear leadership.