Television images from the dawn operation showed people screaming and trying to hit police, who were dressed in riot gear, with sticks.
The square, one block from Rome’s main train station, was strewn with mattresses, overturned rubbish bins and broken plastic chairs.
Hung on the building was a sheet made into a banner saying: “We are refugees, not terrorists,” in Italian. A small fire burned on the pavement and a sheet hanging from a first-floor window was set alight by squatters inside.
Witnesses who arrived at the square after the clearance operation described a scene of carnage.
“When I arrived at about 9am trash was scattered all over. About 50 people were still in the square, which had been partially closed down to traffic in the meantime. They were sad, frustrated and with no idea where to go,” said Francesco Conte, founder of TerminiTv, an online channel based in Rome’s Termini train station.
About 100 people had occupied the square since Saturday, when most of about 800 squatters were evicted from an adjacent office building they had occupied for about five years.
Police said the refugees had refused to accept lodging offered by the city and that the operation was also necessitated by the risk presented by the presence of cooking gas canisters and other flammable materials in the square, which is surrounded by apartment buildings.
Most of the squatters were Eritreans and Ethiopians who had been granted asylum. Many have been in the country for up to a decade. They ran the building as a self-regulating commune that outsiders were not permitted to enter.
The refugees have previously complained that the accommodation offered to them elsewhere is not of a permanent nature, and that moving would result in the community they have established being split up. The area around the square is full of shops owned by the refugees’ compatriots.
In a statement, the police said the refugees had gas canisters, some of which they had opened, and officers had been hit by rocks, bottles and pepper spray. Two people were arrested.
The vast majority of refugees and migrants reaching Europe this year have landed in Italy, according to the International Organisation for Migration. Public opinion is increasingly turning against newcomers as well as those who have been in the country for a number of years.
“The authorities need to urgently find appropriate, alternative housing, and investigate the use of force by the police during the eviction,” said Judith Sunderland, associate director for Europe at Human Rights Watch. “It’s hard to see how the use of water cannon on people was necessary or proportionate,” she said.