There were no immediate reports of injuries or deaths.
A huge plume of black smoke rose from the reinforced concrete building named the Torre dei Moro that was visibile for kilometers (miles). Flames continued to burn inside nearly 3 hours after a dozen fire trucks and ambulances responded to the alarm.
One firefighter told the Corriere della Sera newspaper that the blaze was still limited when they arrived and firefighters were able to get to the top floor to evacuate residents. Within an hour, the flames had spread from the 15th floor, where it appears to have started, quickly devouring the entire facade of the building.
The 60-meter (nearly 200-foot) tall building, part of a recent development project, was designed to look like the keel of a ship and included an aluminum sail on its roof, which burned and fell to the street in pieces.
Firefighters say the fire involved a 20-story building. Plans for the project say it has 16 residential floors plus two underground.