Police are on alert at several Italian stations amid threats from protesters to disrupt high-speed trains on the first day of a Covid pass, APA reports citing BBC.
The "green pass" is now compulsory for domestic flights, ferries and long-distance or fast trains as well as schools and universities.
Increased security was reported at stations at Rome, Florence and Rimini.
Foreign Minister Luigi Di Maio has condemned a climate of hatred over the launch of the pass.
He is one of several public figures to have been targeted by anti-vaccination protesters in recent days. Journalists and medical experts have complained of being stalked while Mr Di Maio faced death threats online.
The pass, both digital and on paper, provides proof of at least one Covid-19 vaccination, recent recovery or a negative test. It is already required for entering cinemas, restaurants, gyms and swimming pools, but it is not needed on local buses.