As many as 700 police officers have been on patrol in Venice since the early hours of Saturday morning in anticipation of an unauthorised demonstration by anarchists scheduled for 3pm in the Campo Santa Margherita.
With tensions high in the city, many local businesses in the area have boarded up their shopfronts and closed for the day. Tourists in the area are being moved on by police.
Police have also been carrying out checks on new arrivals in the city at the Ponte della Liberta, according to La Nuova di Venezia e Mestre. The extra security has caused long queues and traffic on the bridges that connect the historic city with the mainland.
Around 200 anarchists are expected in the city, with some even travelling from outside Italy.
The demonstration has been organised in support of Juan Antonio Sorreche Fernandez, a Spanish citizen sentenced to 28 years in prison by a Treviso court for planting a bomb at the headquarters of Lega di Villorba in 2018.
As of 2pm, La Nuova reports that the Campo Santa Margherita is calm but that demonstrators had started to arrive in the city.
Business and tourist activity continues as normal in the rest of the city.