Rescue workers searching the rubble of an apartment building destroyed by a gas explosion last week in Rosario, Argentina's third-largest city, on Monday found another body, bringing the confirmed death toll to 19.

The body found on Monday is that of an 86-year-old woman, municipal Health Secretary Leonardo Caruana said.

He said authorities will continue the search for two people still listed as missing in the wake of the powerful explosion last Tuesday that toppled the 10-story building and damaged two other structures in downtown Rosario.

The explosion damaged the homes of 240 families who have not been able to return.

Investigators are focusing on the gas company employee who was working at the building before the blast and remains under arrest.

Litoral Gas, the Belgian-Argentine utility that serves the area, is also under investigation for having "very limited and primitive" controls in place, prosecutors said. EFE