Two Chelsea supporters were admitted to hospital after suffering non-life-threatening injuries on Tuesday night in Naples.
Italian police told Sky Sports News one was treated at the Vecchio Pellegrini hospital for a wound after an incident near the Santa Maria La Nova area in Naples. The supporter has since been discharged.
Police added that the supporter was with a group of Chelsea fans, who were then met by another group of people.
The Blues are in the Italian city ahead of their Champions League game against Napoli on Wednesday night.
Chelsea have urged all visiting fans to take "extreme caution" ahead of the match, and follow club guidance.
The Blues have an allocation of 2,500 away tickets for the Champions League fixture.
A Chelsea statement issued on Tuesday night read: "The club is aware of an incident that took place on Tuesday evening in Naples.
"Two fans are being treated in hospital, having sustained non-life-threatening injuries.
"The club would like to remind all supporters to exercise extreme caution whilst in the city and take note of the advice shared ahead of this fixture."
