A total of 20 individuals, 14 locals and four Albanian nationals, were arrested on the holiday island of Rhodes on Monday following a lengthy investigation into a drug trafficking network on the isle.
Nineteen residences were also search, in the presence of prosecutors, during the operation, which uncovered an unspecified amount of heroin and cocaine, police said.
The suspects ranged in ages from 26 to 71 years old.
Authorities believe ring is masterminded by a gang of prison inmates.
According to reports, suspects used the courtyard in front of the island's largest detoxification centre as a more-or-less outdoor "bazaar" to sell narcotics to users.