The Greek Police (ELAS) arrested five people during a crackdown at dawn in the central Athens district of Exarchia.
It was the second operation in as many days within the framework of a government plan to eradicate lawlessness in the area, which has a reputation for being an anarchist stronghold.
Three people were arrested for drug dealing, one for theft and another for selling pirated CDs.
The operation coincided with the publication of a letter from residents of Kallidromiou Street, denouncing a criminal gang conducting robberies at will in the area around the local police precinct.
In a separate incident near Exarchia on Friday, around 20 hooded individuals stormed out of the Athens University of Economics and Business, pelting officers of the Dias motorcycle unit that were on duty in the area with rocks and other objects.
No one was injured or arrested in the incident, but one of the perpetrators stole a wireless radio from one of the officers.