A group calling itself the Group of Popular Fighters has claimed responsibility for an attack on the Israeli embassy in Athens in December.
An unidentified man called at the Efimerida ton Suntakton newspaper late Tuesday to say that a statement, recorded on a memory stick, had been left inside a garbage bin in Nea Smyrni, south of Athens.
Police were examining the device for possible evidence. The content of the USB stick has yet not been made public.
According to witnesses, four people on two motorcycles fired shots at the embassy building in the northern suburb of Psychiko, on December 12. No one was injured in the attack.
In January 2013, the group attacked the headquarters of then ruling New Democracy party on Syngrou Avenue. It has also claimed responsibility for an attack against the German ambassador's residence in December 2013.