Serie A leader Inter Milan has become the second Italian team in two days to receive a threatening letter with bullets inside the envelope.
The unsigned letter, that arrived on Friday (local time), told Inter's chairman Massimo Moratti to be 'very, very careful', the ANSA news agency reported. The letter also insulted and threatened Inter coach Roberto Mancini and striker Zlatan Ibrahimovic, who is the joint-top scorer in the league with 13 goals.
Police confirmed the existence of the threatening letter but would not discuss the content. An Inter spokesman declined to comment.
A similar unsigned letter arrived at the offices of AC Milan a day earlier in an envelope that contained a bullet. The letter threatened Milan president Silvio Berlusconi - the former Italian premier who is also the head of Italy's centre-right opposition - as well as club vice-president Adriano Galliani and coach Carlo Ancelotti.
A Milan spokesman said it was not the first time such a threat had been received, but he could not remember the last occasion.
Former Italian referee Pierluigi Collina - who now selects and trains match officials - has had a security detail since November. Collina received a threatening letter late last year that Italian officials deemed to be serious, news reports said.