STORY: The building, in Lima's San Martin Plaza, was empty when the massive blaze ignited from unknown causes, local media reported.
Video footage showed firefighters battling to contain the blaze that had consumed the building. Authorities have not yet reported what caused the fire.
General Commander of Lima’s Fire Brigade Mario Casaretto said firefighters worked to prevent the fire from spreading to nearby buildings.
Hours earlier on Thursday, thousands of protesters, many from the country's heavily indigenous south, led anti-government protest in Lima, angered by a mounting death toll since unrest erupted last month and calling for sweeping change.