Organisers of the 2016 Olympic Games in the city also expressed their faith in security measures.
At least 30 people have been killed this week in Rio in five consecutive days of fighting.
The city will be a key venue when Brazil stages the 2014 World Cup and is widely tipped to host the final at the Maracana. Two years later, it will become the first South American city to host the Olympics.
"I ratify the confidence in the public authorities and recognise the effort by the state government of Rio de Janeiro with the aim of reducing urban violence," said Brazilian Football Confederation president Ricardo Teixeira in a statement.
"It can be seen that society is reacting strongly against the incidents provoked by criminals, in a demonstration that public opinion supports the security policies.
"As a consequence, I can assure the sporting community that host city Rio de Janeiro will have the climate of normality necessary to stage the Confederations Cup in 2013 and the World Cup in 2014."
Brazilian authorities have claimed that recent attacks by drugs gangs are a desperate response at police efforts to take control of their turf in more than a dozen slum areas.
The local organising committee of the Rio Olympics also promised a trouble-free games.
"The Rio 2016 committee has full confidence in the security plans which have been elaborated jointly with the three levels of government (municipal, state and federal) and presented to the International Olympic Committee (IOC)," it said.
Urban crime is a major worry for both events.
Gang violence has spilled over several times since Rio was awarded the 2016 Olympic Games in October 2009.
Gang members shot down a police helicopter weeks later, sparking police raids and violence that resulted in 30 deaths.
In August, gunmen from a slum armed with automatic weapons and grenades invaded a five-star hotel in one of Rio's richest neighbourhoods and held 35 people hostage for two hours.
This month's Brazilian Grand Prix in Sao Paulo was marred by armed attacks on world champion Jenson Button and a group of team engineers.
Cities such as Rio are also plagued by bus hold-ups, in which armed gangs board buses and rob all passengers between stops, car-jackings and so-called express kidnappings, in which victims are taken to cashpoints are forced to withdraw money at gunpoint.
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