An explosion apparently caused by a gas leak ripped through a restaurant in downtown Rio de Janeiro early on Thursday, killing at least three people and wounding at least 13, officials said.
Three of the wounded were said by rescue officials to be in a grave condition following the blast, which showered the street and a nearby square with debris and disrupted rush-hour traffic in Brazil's second-largest city.
Rio is struggling to address concerns over poor infrastructure as it prepares to co-host the soccer World Cup in 2014 and the Olympic Games two years later.
"The dead are three adults who probably worked in the restaurant. There are strong indications that it was caused by a gas leak," Gil Kempes, an official with the state's disaster response center, told Reuters.
The restaurant was at the base of a multi-story building and firefighters ordered the evacuation of surrounding buildings while they checked for possible structural damage.