BERLIN, June 20 (Xinhua) -- The Office for the Protection of the Constitution (BfV) has expressed concern on Wednesday over a growing security risk posed by left-wing extremists in Germany.

"The current level of violence and aggression on behalf of left-wing extremists against police officers, as well as civilian individuals and institutions is worrying", BfV president Hans-Georg Maasen told the press in Berlin.

Left-wing extremists in Germany have traditionally showcased a preference for non-violent protest. Maasen stressed, however, that members of the scene increasingly justified violence against the state and police in their rhetoric on the grounds that they allegedly served as "instruments of repression."

According to the BfV president, there was consequently an urgent need for a societal debate in Germany over how to respond to the threat of violent left-wing extremism. "Violence cannot become acceptable as a legitimate course of action in political conflict", Maasen warned.

Figures compiled by the BfV indicate that the number of left-wing extremists who were potentially violent has increased by 27 percent between 2012 and 2017 from 7,100 to 9,000 individuals. During the same period, recorded incidences of left-wing extreme violence rose by 88 percent to a total of 1,648, while general criminal offenses motivated by a left-wing extreme ideology increased by 99 percent to 6,398 offenses.

The group "Interventionist Left" (IL) was identified by the BfV as the single most significant left-wing extreme group operating in Germany. The government agency accused the IL of pursuing a thinly-veiled strategy to radicalize its members.