Updated

RIO DE JANEIRO-- An explosion likely caused by a gas leak ripped through a restaurant in downtown Rio de Janeiro on Thursday, killing at least three people and injuring 13, officials said.

The explosion around 7:30 a.m. caused heavy damage to the restaurant, which wasn't open, and to the apartments above it, said Ronaldo Alcantara, the second in command of Rio's fire department, who was at the site of the explosion.

"The three fatal victims were flung outside the building," Alcantara said.

Firefighters and the city's civil defense department are searching for more victims, though no people are known to be missing, he said. And they are investigating the cause of the explosion, though Alcantara said it was likely caused by a gas leak.

The restaurant had been closed on Wednesday, a holiday, and gas had probably leaked throughout the day and night. When the restaurant's first employees arrived Thursday morning, they may have somehow caused a spark that ignited the gas, said Alcantara.

Two of the victims have been identified as restaurant employees, he said. Three of the injured are in serious condition and have been taken to a local hospital.