Brazil World Cup anti-terror law divides opinion
Congress is currently considering Bill 449, which would create a penalty of 15 to 30 years in prison for "causing or inciting widespread terror by threatening or trying to threaten the life, the physical integrity or the health or liberty of a person".
Although Brazil has had no major terrorist incident for many years, advocates say that the country must be prepared because of its growing international profile and is acting as host to foreign sports fans, teams and dignitaries.
Campaigners, however, fear that the legislation will be used to suppress anti-government protests.
Lawyers, politicians, NGOs and protest organisers warn that the current wording of a bill submitted to the Brazilian National Congress is dangerously vague and could allow security forces unprecedented powers to arrest demonstrators.
"This already happens without without this law. It's clear this is just one more plan of this system. It's all a façade. The truth is they don't want any protests," a Black Bloc member responded from the group's Facebook account.
"We're not going to accept rules from these corrupt people and they certainly know that."