BERLIN, Nov. 15 (Xinhua) -- In a major police operation, 560 officers and special forces (SEK) searched apartments of alleged left-wing extremists in Berlin on Thursday.

"The background is an investigation by Berlin prosecutor's office into grievous bodily harm," said a police spokesman.

The Rigaer street in Berlin, which is considered by German authorities as a hotspot of left-wing criminal activities, was at the focus of the police operation.

The police operation was sparked by an attack on a shop owner in Berlin by a masked group in May 2018. Allegedly, a woman had hired the group to punish the shop owner after he refused to give out a parcel.

According to a tweet by Berlin police, four houses have been searched to gather evidence but only few of the suspects whose apartments were searched are under official investigation.

Berlin's senator for interior Andreas Geisel (SPD) is demanding better video surveillance in Germany's capital.