The downing of a police helicopter by Rio de Janeiro drug gangs on Saturday has triggered criticism that parts of the future Olympic city resemble a war zone. Brazilian police now claim to have killed two suspected drug traffickers and arrested four others in a weekend of battles which have left at least 15 people dead.The upsurge in violence has come as a blow to Rio’s image just two weeks after it was awarded the 2016 Olympic games. Jose Mariano Beltrame who is a state public safety director is confident the security problem can be solved: “We told the committee that Rio de Janeiro has a safety problem,” he said. “We are fully aware of this problem, it is one of the city’s most historic problems. We proved to the Olympic Committee that we have plans and proposals for Rio.” Two policemen were killed in the helicopter crash and four other officers were crew badly burned. Rio has a reputation as one of the world’s most violent cities, with almost daily shoot-outs between police and armed gangs. Officials played down the security problems during the bid for the Games.