The accident occurred shortly before closing late Thursday when an adjacent building under construction collapsed in the city of Neuquen, damaging the structure supporting the market's roof while dozens of customers shopped inside.
Provincial civil defense chief Vanina Merlo earlier suggested that six people were missing but a civil defense official who spoke on condition of anonymity said the number of missing was unknown.
Merlo told reporters that emergency workers were moving carefully given the risk of a further structural collapse, warning that there could be more victims. Three truckloads of debris already have been removed.
"The ceiling fell two meters (seven feet) from where I was standing and then I was stuck with two or three people in a hole, and a policeman helped us out a side door. I was saved by a miracle," a customer who gave her name as Paula, told TN television.
Neuquen, a city of 300,000 about 1,150 kilometers (715 miles) southwest of Buenos Aires, is the capital of the eponymous state.
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