A group calling itself the “Detonators of Social Uprisings” has claimed responsibility for the arson attack on a local government office in Kavala, northern Greece, on Thursday.

The previously unheard-of group said it was expressing solidarity with anarchist Costas Sakkas, who has been on hunger strike since June 4 to protest being held in pretrial custody for two-and-a-half years.

It is estimated the damage caused by the attack is worth more than 100,000 euros.