Rio, which will stage seven matches including the July 13 final, was the scene Tuesday of angry protests and clashes between residents of a slum district a short walk from the popular Copacabana Beach and police.
Trouble broke out after a dancer was found dead, with friends and family alleging he was shot by police. In the ensuing protests, a 27-year-old man was fatally shot.
"It is a tragic episode which causes sadness but it is not sufficient to say the Cup is at risk," Valcke told reporters.
He winds up his latest check on Brazil's World Cup preparations in Rio on Friday.
Earlier Thursday, FIFA announced there would be 12 World Cup fan fests, including the northern city of Recife, where authorities had previously said it would not go ahead on cost and security grounds.
Fan fests -- huge street parties for ticketless fans -- proved successful on their launch at the 2006 World Cup in Germany and continued in South Africa in 2010.
Some officials are also fearful that the venues could become focal points for protests of the kind that marred last year's Confederations Cup.
