Rival demonstrations by far-right and anti-fascist groups a week before Italy’s general election have led to scuffles with police.
Police in Milan used batons as left-wing demonstrators tried to break through a cordon.
Elsewhere, the leader of the anti-immigration League party, Matteo Salvini, told supporters that defence of the country was a “sacred duty”.
Protests also took place in Rome and the Sicilian city of Palermo.
As the election campaign enters its final week, opinion polls suggest that the right-wing Forza Italia party led by former Prime Minister Silvio Berlusconi is in the lead.
The anti-establishment Five Star Movement will be vying with Mr Berlusconi’s party for the top spot in the 4 March election. However, it has repeatedly ruled out governing with other parties.
The far-right League and the Brothers of Italy parties could attempt to form a right-wing coalition government with Mr Berlusconi but this is unlikely to achieve a parliamentary majority.
Clashes between anti-fascist and far-right activists have increased in recent weeks ahead of a general election on 4 March.
On Thursday, several police officers were injured in clashes between far-left and far-right protesters in Turin.
Riot police clashed with protesters at a campaign rally in Pisa on Friday by the League party.
On Saturday, anti-fascist demonstrators in Milan protested against the anti-migrant stances of far-right parties. When they tried to break through police lines, officers beat them back with batons.
In Rome, some 3,000 officers were deployed for marches and sit-ins on Saturday. Riot police used metal detectors in a series of measures aimed at preventing violence.
Several thousand people took to the streets of the capital to protest for democratic values and against what they described as resurgent fascism.
Former Italian Prime Minister Matteo Renzi took part in a rally which was arranged by the National Partisans’ Organisation (ANPI) under the slogan “Fascism Never Again”.
At the same time in the city, a protest led by the left-wing union group Cobas marched against the labour reforms known as the Jobs Act. The reforms were a signature policy of Mr Renzi’s government.
Meanwhile, consecutive marches in Palermo in northern Sicily are expected to be attended by Roberto Fiore, the head of the far-right group Forza Nuova, and members of a far-left movement.