Two adjacent buildings collapsed Wednesday night in the historic center of Rio de Janeiro in Brazil injuring at least four people, Mayor Eduardo Paes told reporters.
It was not immediately clear what caused the collapses -one a 20-story building and the other 10 stories- nor was the extent of the casualties clear, the CNN reported.

Paes did not rule out the possibility of a gas leak, but other hypotheses included the possibility of structural failures in the buildings, which were located behind the Municipal Theater.

Fire officials said at least four people were injured. the CNN reported that 11 people were missing in the collapses. Witnesses said that neighboring buildings swayed, as if there had been an earthquake. 

One witness said many people were inside one of the buildings when it collapsed.

The buildings are in a bustling commercial and financial area of Rio de Janeiro.
Source: BNA