Brazilian cops enlist FBI's help in quelling unrest around World Cup sites
The Special Riot Police unit (CHOQUE) carries out a drill for controlling civil disorders, at their headquarters in Rio de Janeiro, Brazil, on May 15, 2014 [AFP]

Brazilian police compared notes with U.S. law enforcement officers here Thursday as they geared up for a mammoth security operation at next month's World Cup.

With fresh protests against the tournament rippling across Brazil, a gun-toting shock battalion of Rio military police held a mock crowd control drill complete with helicopter and fake tear gas.

Military police Colonel Andre Vidal said input for US advisers had been useful as Brazil prepares to drape a 170,000-strong World Cup security blanket across the June 12-July 13 tournament.

"We will not be changing our modus operandi for the World Cup," Vidal stressed, while adding information-sharing was a useful means of determining "how to act in the best way possible" during the World Cup.

"This is an exchange of experiences to learn from different countries," said Vidal. The Brazilians have also studied riot policing techniques in European countries including Spain and Germany.

Vidal reiterated that peaceful protests against the cost of the World Cup would be tolerated provided they did erupt into violence.

"Demonstrations are permitted in Brazil, but what is not permitted is civil disturbances," the colonel told reporters in Rio.

The U.S. Federal Bureau of Investigation agents present declined to comment.

In March, the Brazilians oversaw a week-long training session with FBI agents in the city of Belo Horizonte, covering topics such as organized crime, peacekeeping techniques and respecting marchers' human rights.

Brazil's branch of Amnesty International this week expressed concern that a planned crackdown on protests may comprise human rights such as freedom of expression.

"Protesting is not a crime, it is a human right," said Amnesty's Brazil director Atila Roque.

The Brazilian senate is due to vote on proposals to pass a law making public "disorder" a crime.

But Amnesty fears the move could criminalize people simply attending a protest.

[Image via Agence France-Presse]