Rome officials are defending their decision to evacuate hundreds of refugees occupying an abandoned building in the city center after protests from the U.N. refugee agency, UNICEF and humanitarian organizations.

Police began clearing out the building at dawn Saturday, the latest of several such operations as Rome and other cities struggle to find accommodation for new migrants and face mounting anti-immigrant sentiment from voters. Police have defined some of their raids as "anti-terrorism" operations.

Many of the squatters refused to leave the building, near Rome's Termini train station, and others have been sleeping outside since Saturday. Tensions again flared Wednesday morning when police tried to enter the building, occupied since 2013.

Refugees threw paint, garbage and bottles to the ground, and unfurled a banner: "We're not terrorists. We want housing."