At least three people were killed and more than a dozen others injured after the roof of a supermarket in western Argentina broke down, local authorities said Friday. The tragedy in the city of Neuquen, 1,150 km southwest of Buenos Aires, occurred Thursday night when an adjacent building under construction collapsed and crushed the supermarket\'s roof shortly before its close hour. Dozens of people were shopping inside when the accident happened, according to local officials. There have been no definite reports about how many were still trapped inside. Three truckloads of wreckage have been removed, but the danger of further collapses has prevented rescuers from get inside the ill-fated structure, they added. With rescue efforts going on, Governor Jorge Sapag of Neuquen Province has reportedly decreed three days of mourning.