Fifa president Sepp Blatter has called on Brazil's protesters to stop linking their demonstrations to football, as police stepped up reinforcements ahead of expected clashes at Confederations Cup matches taking place in Rio de Janeiro and Fortaleza.

After protests on the fringes of earlier games, boos during official speeches in the stadiums and placards on the streets condemning Fifa, the head of the world football body said the tournament – a dry run for next year's World Cup – was being wrongly targeted.

"I can understand that people are not happy, but they should not use football to make their demands heard," Blatter said on Globo TV, a domestic station.

His appeal looks likely to fall on deaf ears. Protesters on Wednesday blocked the road to the stadium in Fortaleza, where Brazil were due to play against Mexico. Police turned back hundreds of cars.

There is also a Twitter and Facebook campaign for spectators inside the ground to turn their backs when the national anthem is played.

Several of Brazil's national team players have also expressed their support for the demonstrators.

"I see these demonstrators and I know that they are right," the midfielder Hulk told a press conference in Fortaleza.

"We know that Brazil needs to improve in many areas and must let the demonstrators express themselves."

Brazil is in the midst of its biggest wave of protests in 20 years. Initially sparked by police violence against small demonstrations against bus price rises, the protests have rapidly expanded in size, range and motivations.

On Monday night, a quarter of a million people rallied in more than a dozen cities to express a range of grievances, including dire public services, corruption and evictions.

Fifa's tournaments have become a focus for many demonstrators, who feel the 12 stadiums that the country has built or renovated at huge cost show how public money is spent on projects that benefit construction companies and TV stations rather than on hospital and schools.

This argument has been eloquently expressed in English in a popular YouTube video titled "No, I'm not going to the world cup" which has drawn more than 1.5m views.

The video's narrator, Carla Dauden, said: "Suddenly there is all this money available to build new stadiums and the population is led to believe the World Cup is the change they need for their lives to get better. But the truth is that most of the money from the games and the stadiums goes straight to Fifa and we don't see it so we don't get it and the money from tourists and investors goes to those who already have money."

The government says the $13.3bn spending on the tournaments is also being used to improve roads, metro services, airports, communications and public security – all of which would help to boost the country's economic and social development.

This point was emphasised by Blatter, who said Fifa did not impose the tournament on the hosts. "Brazil asked to host the World Cup," Blatter said. "They knew that to host a good World Cup they would naturally have to build stadiums.

"But we said that it was not just for the World Cup. Together with the stadiums there are other constructions: highways, hotels, airports … Items that are for the future. Not just for the World Cup."

He and Brazilian president Dilma Rousseff were booed by the crowd at the opening ceremony of the Confederations Cup on Saturday.

This are unlikely to be the last insults they hear. The football tournament will run until 16 July.

The protests are expected to escalate with bigger rallies planned for Thursday. Despite Blatter's appeal, it is unlikely the two will remain apart.