Fifa concerned over Brazil violence
Fifa says it is concerned about recent violence in Brazil less than two months before the country hosts the World Cup, but football's governing body is still confident Brazil will stage "the biggest party on Earth".
Marketing director Thierry Weil spoke after a Rio de Janeiro slum erupted in violence on Tuesday following the killing of a popular local figure.
Angry residents started fires and hurled home-made explosives and bottles on to a busy street in the city's main tourist zone.
It was the latest violence to hit one of Rio's so-called "pacified" slums - poor areas that were long controlled by drug gangs.
Police began an ambitious programme in 2008 to drive gangs from slums. The action is part of Rio's security push ahead of the World Cup.
Meanwhile residents of the Pavao-Pavaozinho "favela" slum staged a protest in the Copacabana beach neighbourhood.
Several hundred people took to the main thoroughfare of the neighbourhood in the protest. It appeared to be largely peaceful, despite reports of an initial scuffle between demonstrators and police.
The protest followed the burial of Douglas Pereira, whose shooting death sparked Tuesday's clashes between police and residents.
Rio state's top security official has acknowledged Mr Pereira may have been shot by police.
The slum is sandwiched between two of Rio's highest-rent neighbourhoods and just a few hundred yards from a key venue for the 2016 Olympics. Another young man was killed in the conflict.
"Yes, there are security issues but those matters lie with the government and state of Brazil and that is a part of the commitment they have given to us. Fifa cannot ensure security," her said.
"But be optimistic, football is optimistic this will be a great tournament in a country where football is revered."
Mr Blatter also said there had always been some issues in the lead-up to the World Cup. Three stadiums in Brazil have still not been completed.
"There are problems but I have never seen a World Cup where everything was ready before it kicked off. I have been to 10 World Cups and every time there have been worries," he said.
"We are just about one month away from this World Cup and I'm optimistic it will be a great tournament."
Meanwhile protesters holding banners and placards demonstrated peacefully at the inauguration of the Hong Kong Football Association's new offices, to highlight the plight of migrant workers building stadiums in Qatar for the 2022 World Cup.
The International Trade Union Confederation has complained about the exploitation of migrant workers and deaths related to dangerous conditions on building projects in Qatar in the years since the 2022 World Cup was awarded to the Gulf nation.
In recent months Qatar has sought to allay widespread concerns about conditions for workers on World Cup building projects by detailing how their rights must be protected by contractors. Organisers are also considering scaling back the number of venues for the tournament.
Mr Blatter distanced Fifa from the issue and said it was a matter which only the local authorities could handle.
"They have a problem and we know that but this is not directly a question for Fifa," he said. "It is one which the state of Qatar must handle as well as all the construction companies who are responsible for the workers."
Mr Weil told reporters in Rio that while the images being broadcast around the world of the riots were not pretty, "we strongly believe in the country, in the cities, in the government and their advance of security".
"From our commercial partners, which will bring a lot of guests to Brazil, for sure there are lots of discussions on the riots, whether it will happen again like it did in the Confederations Cup, so there are lots of questions.
"But I can guarantee that no one has retracted from bringing guests because everybody strongly believes that this will be the biggest party on Earth."