ATHENS, March 15 (Xinhua) -- Two Greek guerrilla groups claimed on Friday responsibility for a bomb attack at a courier firm in Athens on March 10, which caused material damage, while warning of more violence ahead, local media reported.
The so-called "Informal Anarchist Federation" and the "International Revolutionary Front- Intact Revolutionary Cell" groups released a statement saying that Sunday's attack was to "take revenge" on an employee of the firm who helped in the arrest of terrorists two years ago.
In November 2010 a parcel bomb addressed to a foreign embassy in Athens went off at the hands of an employee inside the same courier company.
The incident triggered a police investigation which led to the arrest of members of the "Conspiracy of the Nuclei of Fire."
Accusing the employee for "deadly curiosity," extremists threatened that they intend to attack more targets on their black list, including police officers and judges presiding over the trials of "Conspiracy of the Nuclei of Fire" members.
Greece has a long history of domestic terrorism. Following the outbreak of the debt crisis in 2009 which has led the country to the brink of bankruptcy, several groups have linked attacks with harsh austerity measures implemented to resolve the crisis.
In January, unidentified assailants opened fire at the ruling party headquarters, and a few days later, a strong bomb blast occurred inside a shopping mall, slightly injuring two guards.