Greek police say they have detained 25 anarchists who burst into the cathedral in the northern city of Thessaloniki and interrupted a Mass, chanting slogans and dropping flyers.

The anarchists on Sunday were protesting a police operation Wednesday that evicted anarchists and refugees from three illegally occupied buildings in the city. One of the buildings, formerly an orphanage, is the property of the Greek Orthodox Church and is being demolished. Police had arrested 74 anarchists in the operation, 64 of them foreigners, from Austria, Denmark, France, Germany, Great Britain, Italy, New Zealand, Papua New Guinea, Spain and Switzerland. The 33 refugees were freed.

Before dawn Sunday, an improvised device exploded outside the offices of the construction company demolishing the church's property but did little damage.