ATHENS, Dec. 27 (Xinhua) -- Greek urban guerrilla group OLA (Popular Fighters Group) on Wednesday claimed responsibility for a pre-dawn bomb attack which caused damage but no injuries at the Athens Appeals Court on Dec. 22.

Attackers opened fire with a semi-automatic rifle on a guard who had noticed them leaving a bag at the entrance of the building, but missed their target, police said.

In a statement on an anti-establishment website, the group claimed that the "judicial system is not blind, but serves the interests of capitalists."

In recent months, protesters have stormed court building in attempts to stop the auction of foreclosed properties. Last week, the Greek parliament passed measures to impose heavier penalties on protesters.

has been suffering from domestic terrorism over the past four decades. Despite the dismantling of many groups, a new generation has taken over after the start of the in 2009.

OLA also claimed responsibility for an attack, with semi-automatic rifle, on the headquarters of the conservative New Democracy party and a similar attack on the German ambassador's residence in 2013.