Explosions damaged a car near a post office in central Rome on Friday, Italian media reported, although nobody appeared to have been injured in the blast.

"Double explosion in Rome ... initial information from the scene indicates no one was injured. Only one car damaged," state broadcaster RAI said on its website, quoting an emergency services worker saying the situation was "under control".

Information service Luceverde, run by the Italian Automobile Club in collaboration with city police, said on Twitter that an area near the site of the ancient Circus Maximus racetrack had been closed for security, but traffic was not affected.

RAI said two devices had been found near parked cars in the area, where authorities were exploring all possible causes, including that the explosive may have been a letter bomb or a similar improvised device. Television footage showed police officers and firefighters at the scene, and police tape blocking off part of the street.