Emergency personnel are searching for survivors among the wreckage of two collapsed buildings in downtown Rio de Janeiro Wednesday night.  There are conflicting reports regarding deaths from the collapse of the 20-story and 10-story buildings with the Brazilian newswire Agencia Estado reporting two people killed, but Rio Mayor Eduardo Paes told Reuters no deaths have been reported and that four people have been rescued from the wreckage.

 Confirmed information is still hard to come by and a Reuters report relied heavily on reports from other sources.

“A loud explosion preceded the collapse, which left the surrounding area covered in debris and dust, witnesses said.

‘It was like an earthquake. First some pieces of the buildings started to fall down. People started to run. And then it all fell down at once,’ a witness who identified himself as Gilbert told Reuters. 

As many as 11 people could be trapped in the wreckage, cable broadcaster Gloominess said. City authorities are assessing the risk of collapse of a damaged adjoining building, local newswires reported, without giving the source of the information. 

‘I ran down the stairs desperate to escape. Just when I left the building it collapsed. I escaped by the skin of my teeth - it's the work of God,’ Nelson Tomes, 38, an air conditioning technician, told iG newswire.”

According to the Washington Post, a strong, possible natural gas odor, could be smelled in the area, but the mayor did not believe a gas leak was the cause of the collapse.

“There apparently was not an explosion. The collapse occurred because of structural damages,” Paes said. “I don’t think there was a gas leak.”

Building safety is a major concern in Brazil, and specifically in Rio, ahead of the country's upcoming Olympic and World Cup hosting duties.