THESSALONIKI — Greek police say the entrance of a French cultural institute in the northern city of Thessaloniki has been damaged in an attack by about a dozen youths who hurled rocks at the building, smashed windows with bats and sprayed foam from a fire extinguisher.

No one was injured in the incident that occurred early Monday at the Institut francais, before opening hours.

The Greek Foreign Ministry issued a statement in French condemning the attack as an “act of barbarism.”

Police made no arrests and there was no immediate claim of responsibility.

Anarchist groups in Athens and Thessaloniki frequently attack banks and symbols of authority, as well diplomatic property, in support of fellow anarchists detained in others countries.