A powerful blast from a gas leak ripped through a ten-story apartment building setting it ablaze in Argentina's third largest city Tuesday, leaving at least eight dead and 61 injured.

And city officials in Rosario said at least 19 people were still missing as hundreds of firefighters and rescuers searched the rubble of the edifice that was in danger of collapse.

"There are 8 dead. The search in the rubble will continue all night," Mayor Monica Fein said at a press conference.

"There is a list of 19 people whose families said they have not been heard from."

The blast wiped away the front of the building, leaving the insides of people's homes and gutted balconies visible from the street below.

Among the wounded was at least one child who suffered head injuries, hospital officials said.

Rosario's health ministry declared an emergency, calling all dispatchers into action.

Mayor Fein said earlier 17 ambulances were on the scene to help people injured in the fire.

People within a two-kilometer (one-mile) radius of the explosion, including 11 schools, were evacuated, as the gas supply to the building could not be cut off.

Civil defense officers were able to rescue survivors via the roof of a neighboring supermarket.

But civil defense director Raul Reinone said that the magnitude of the event may cause the building to collapse.

"The shock wave was tremendous," the superintendent of a building 200 meters from the site of the explosion told the TV station C5N.

"This is awesome, I've never seen anything like this in Rosario. I remember the images of the AMIA", German Martinez, 40, who is employed in a neighboring office, told AFP, referring to the attack that destroyed the Argentina Jewish center in Buenos Aires in 1994, with a death toll of 85 and 300 injured.

The blast sent flames roaring through the building as fire truck sirens sounded and traffic clogged Rosario's city center. The area around the building includes shops, schools and banks.

Following the blast, people ran through the streets or gawked at the ruined structure, some of them crying.

Shards of shattered glass littered the streets.

Rosario is home to 1.1 million people and is located 300 kilometers (180 miles) north of Buenos Aires. It is Argentina's main port for farm exports.