Several cars could have fallen down, according to the broadcaster. A rescue team is currently at the scene of the incident. The bridge has been closed to traffic.
At the same time, the head of the local ambulance service said there were "dozens of dead", Italian news agency Adnkronos reported. According to the local fire brigade, the bridge collapsed at around 11:30 a.m. local time during torrential rainfall.
"The scale is epochal. There are dozens of dead among those who fell from the bridge or got trapped under the rubble," Francesco Bermano said, as quoted by the Adnkronors news agency.
The bridge was developed by architect Riccardo Morandi and built in 1968. It's said to be the first cable-stayed bridge in Europe.
Italian Transport Minister Danilo Toninelli has turned to Twitter to comment on the incident. "I'm following with great apprehension what has happened in Genoa, which appears to be an immense tragedy," Toninelli said.
Twitter users have been sharing photos and videos of the collapsed bridge.