An Italian man has undergone surgery for head injuries after being punched and kicked in the head in a Rome subway car by two men he asked to stop smoking.

Rome city hall said Mayor Virginia Raggi went to the hospital Tuesday to visit Maurizio Di Francescantonio, 37, two days after he was attacked while riding on the subway with his mother.

Prosecutors are investigating the two men, who come from the Caserta area in southern Italy, for attempted murder.

The victim's mother told reporters that no passengers came to her son's aid after he was attacked. She was slightly injured when she tried to end the attack.

Smoking is forbidden on Rome's public transport system.