Hundreds were injured in the blaze that broke out during lunch hour on Sunday at a three-story supermarket in a suburb of Asuncion, the capital. Flames quickly filled the Ycua Bolanos supermarket, food court and parking garage, collapsing one floor.
It was the worst disaster in decades in the impoverished South American country. The cause has not yet been determined, but police said an exploding gas canister may have been the cause.
Many of the victims were burned
Officials also said they were trying to piece together survivor claims that locked doors might have impeded or slowed weekend shoppers trying to escape.
Attorney General Oscar Latorre appealed to survivors to come forward to describe what happened. Authorities set up a table outside the supermarket - a pink-and-white building occupying nearly an entire city block - to question survivors and other witnesses.
"Many witnesses said that security guards had closed the doors," Latorre said.
Juan Pio Paiva, who owns the market with his son, dismissed speculation that the doors had been deliberately locked to prevent looting. He said the building met safety codes and he lamented the deaths.
Officials also said at least 276 were injured, but Channel 4 put its figure at 524. Government officials had no comments on the station's higher totals.
"We couldn't get inside and the people couldn't get out"
Also, investigators were trying to determine how many more were inside the building but escaped unharmed.
Some of the victims were burned beyond recognition, and their caskets are to be marked for possible exhumation in the future to identify the remains, Asuncion Mayor Enrique Riera said.
In one twist of fate, Ruben Aguiar said his family held a candlelit vigil for his missing 23-year-old sister, Marina, only to learn she was found alive but injured.
"This is a moment of such great pain because of this tragedy but my whole family are now overjoyed," Aguiar said.
Rescuers continued to search for bodies, but Police Chief Aristides Cabral said it appeared unlikely they would find more victims.