(CNN) -- Twenty-four Greek nationals, including a priest and a neurosurgeon, have been arrested on suspicion of child pornography, Greek police announced Tuesday.
The arrests followed a sting operation called Myosis, which was conducted across the country. Seven major cities were targeted, including Athens, Thessaloniki and Patra.
Greek police initially acted on a tip from London's Metropolitan Police, relayed by Interpol, leading to a three-month international investigation. Greek police distinguished 35 unique Internet users involved in circulating, selling and purchasing child pornography over the Internet, they said in a detailed statement.
Police were able to identify and arrest 24 of them. Authorities confiscated 28 hard drives, eight laptops and 28,000 gigabytes of digital material on DVD.
Authorities in Greece characterize the material as extremely graphic. Among those shown in the material was a 6-month-old infant with its hands tied up being sexually abused by adults.
Two of those arrested were remanded in custody, while four have been released. The others were due in court on Wednesday to face charges related to the use and distribution of child pornography on the Internet.
The investigation is still ongoing, authorities said.