The shootings have dominated recent days of campaigning for Italy's March 4 parliamentary elections in which immigration is a major issue. More than 600,000 migrants have arrived on Italy's shores from North Africa in the last four years.
Protesters, demonstrating against racism and the return of fascism in Italy, attacked police with sticks and threw stones, while police retaliated with batons as thousands of people took to the streets of Macerata on Saturday in the Italian city where migrant shootings occurred.
The demonstrators carried a range of banners denouncing the return of fascism in Italy.
One placard read "fascist Salvini" a reference to Matteo Salvini, the leader of the right-wing Northern League party which campaigns strongly against illegal immigrants.
However, in a sign of widespread and growing anti-migrant sentiment in Italy, none of the leaders of the main parties attended the march.
The Feb. 3 shootings happened just days after a Nigerian migrant was arrested in connection with the death of an 18-year-old Italian woman whose dismembered body was discovered stuffed into two suitcases near Macerata.
The shooter, 28-year-old Luca Traini, a former Northern League candidate at local elections, told police he was avenging the woman, named as Pamela Mastropietro.