Kathimerini reported Friday that a Greek TV station received a phone call from someone claiming to represent the anarchist group Conspiracy of Cells of Fire, which claimed to be behind the attacks.
The unidentified caller said the attacks represented an act of solidarity for other anti-establishment people currently in prison.
The eight attacks occurred almost simultaneously throughout Attica Thursday, resulting in substantial property damage but no reported injuries.
The early morning attacks appeared to target banks, cars and an insurance office.
Another arson attack occurred Wednesday at former Justice Minister Anastassis Papaligouras' political office. Kathimerini said that attack -- which the previously unknown anarchist group has also claimed responsibility for -- left a woman with minor injuries.