Rescue workers have uncovered the bodies of 17 people killed in the January, 25 building collapse in Rio-de-Janeiro, the state's Civil Defense agency said on Saturday.

Officials believe unauthorized construction work inside a 20-story, 72-year-old building damaged its structure and caused it to crumble, wrenching down two neighboring office buildings of approximately the same age about 8:30 p.m. Wednesday.

The buildings housed offices that had mostly closed for the day and few people were on the normally busy street at the time.

The head of Rio state's Civil Defense agency said the hunt for survivors will continue until Sunday.

City officials said the accident should not cast doubt on Rio's ability to organize and host the upcoming 2014 soccer World Cup and the 2016 Olympics.

"This was an isolated incident that occurred on private property," the mayor's office said in a statement. "The case is entirely unrelated to the preparations for the 2014 World Cup, the 2016 Olympic Games and other events that are already part of the city's calendar."