As church bells pealed and the death toll rose to well over 300, authorities expanded their investigation into reports that locked doors trapped shoppers in a supermarket during a fire, detaining a store manager and a security official.

　　The arrests on Monday brought to four the number of people in custody in connection with Sunday's inferno. The owners, a father and son, were detained for questioning within hours of the disaster. They have strongly denied that doors were locked to prevent theft.

　　The confirmed death toll rose to 323 yesterday, the Attorney General's Office said in a statement. It said without elaborating that 409 others remained hospitalized and at least 139 others were missing.

　　Hundreds were injured in the blaze that broke out during lunch hour 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 this impoverished South American country. The cause had not yet been determined, but police said an exploding gas canister may have been to blame.

　　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.

　　He later said on TV that a store manager and a security official for the store had been detained as part of the investigation.

　　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. Also, investigators were trying to determine how many more were inside the building but escaped unharmed.

　　The first services for victims were held on Monday. In a neighborhood near the complex, some 25 grief-stricken families held wakes and vigils, many after the deaths of children.

　　Some 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 only injured.

　　"This is a moment of such great pain because of this tragedy but my whole family are now overjoyed," Aguiar saids.

　　Rescuers continued to search for bodies on Monday, but Police Chief Aristides Cabral said it appeared unlikely they would find more victims.

　　Cabral said rescue efforts were hampered by fears the building might collapse. Temperatures were still high in parts of the market.

　　Esther benitez, 30, suffered burns and said she at first found her way blocked as she tried to escape. "I ran toward the main door but it was locked," she said.

　　(The Associated Press)