An envelope containing two bullets and a threatening message for former premier Silvio Berlusconi and his brother Paolo was delivered on Friday to the headquarters of the Il Giornale daily.
In the letter accompanying the bullets, the brothers were told they could soon suffer the same fate as Benazir Bhutto, the assassinated Pakistani opposition leader.
The death threat came almost three months after the same newspaper, which is Berlusconi-owned, received a similar envelope addressed to centre-left Premier Romano Prodi and two of his top ministers.
A unit of the Italian police's Digos anti-terrorism division was sent to the Il Giornale newsdesk to investigate.
Prodi's office condemned the ''serious threats'' against the Forza Italia party leader and his brother and called for efforts on all sides to soften the sometimes frantic tone of party politics.
Berlusconi's political allies immediately voiced their solidarity and condemned the act.
MEP Antonio Tajani, a former Il Giornale journalist and a whip for Berlusconi's Forza Italia party in Brussels, said: ''The threats of violent and fanatical people only strengthen our convictions as free men''.
