Theft and labour disruption are the biggest threats to the football World Cup's host cities in Brazil, economy analysts IHS said Monday.
The group said it had examined physical risks to visitors as well as infrastructure and transport constraints and the broader economic and political environment.
IHS said approximately $840 million (620 million euros) was being spent on securing the tournament -- five times the amount spent by South Africa in 2010 -- while around 170,000 security personnel will be deployed.
"The Brazilian authorities have invested heavily on security and defence equipment to combat a wide range of challenges across the 12 host cities," said Laurence Allan, head of Latin America country risk analysis.
Labour unions have become the government's main headache, said IHS, noting that since Rio de Janeiro rubbish collectors secured a big pay increase through strikes, other state employees have threatened industrial action.
Belo Horizonte, Natal, Recife, Rio de Janeiro and Sao Paulo were judged to have a high risk of theft and social/labour protests.
In Rio, "thefts and violent robberies are the most likely risk factors facing travellers", IHS said.
In Sao Paulo, "there is a high likelihood of disruptive social protest with associated vandalism during the World Cup". There was a "slight risk" of street assault around the city centre, it added.
IHS said Fortaleza, Porto Alegre and Salvador were cities with a high risk of theft.
Fortaleza is the seventh most dangerous city in the world, according to the United Nations Office on Drugs and Crime, it said.
There is a significant risk of Argentine football hooliganism in Porto Alegre due to its proximity to the border, while Salvador's carnival is "infamous for street fighting and muggings" and there is a risk of similar incidents during the World Cup.
Brasilia, Cuiaba, Curitiba and Manaus were deemed to have a lower risk of theft and disruption.
"Social protests are certain to occur in many of the host cities," said Allan, but the Brazilian authorities have set up command and control centres which will be able to "flood areas with security personnel" if required.
"However, organisers remain able to coordinate simultaneous demonstrations in several state capitals, and Black Bloc anarchist activists have fought with the police.
"If Brazilian security forces overreact, then we would see a risk that protests would escalate."