A strong bomb explosion occurred on Thursday evening outside of main Athens prison of Korydallos.
At least one person was injured and damages are reported. A police officer speaking on condition of anonymity told local media that there could be a terrorism link behind the attack.
Inside Korydallos are held main suspects of terrorist groups such as the 'Revolutionary Struggle' which was recently dissolved.
The blast occurred shortly after 10:00 p.m. local hour and Greek television channels interrupted their programs to report the incident.
According to earlier information, an unidentified man made a warning phone call to ALTER television channel shortly before the explosion, a common practice of Greek guerrilla groups operating in Greece for years.