The guerrilla group Revolutionary Struggle has claimed responsibility for a bomb that exploded outside the Bank of Greece on April 10, causing serious damage but no injuries, saying that the attack was planned to coincide with the country's return to international bond markets.

In a proclamation posted on the anti-establishment website Indymedia, Revolutionary Struggle said the bomb was a protest at Greece's first foray to capital markets in four years and to a visit by German Chancellor Angela Merkel the following day.

In the proclamation, which is more than 4,000 words long, the organization described Merkel as "the arch-terrorist" and "protagonist of the imposition of extreme neoliberal policies and austerity in all of Europe."

The group called for armed struggle and a "social revolution" to stop an ongoing austerity program in Greece but did not name specific targets for future attacks.

The self-proclaimed leader of Revolutionary Struggle, Nikos Maziotis, and his girlfriend, Panayiota Roupa, have been at large since July 2012 when they disappeared while on conditional leave after serving the maximum of 18 months in pre-trial custody.