PKK-linked People's Protection Units (YPG) supporters injured four Turkish people including one with a knife in Ludenscheid city of Germany on Wednesday.

The 50-year-old citizen was severely injured after being stabbed, and taken under treatment at a nearby hospital, a spokesman for the police said in a statement.

The incident occurred during a protest organized by the YPG/PKK terrorist organization supporters against Turkey's ongoing Operation Peace Spring in northern Syria.

The German police said the incident was still under investigation.

Turkey's Consul General in Essen, Şener Cebeci, visited the injured people at the hospital, as he told them that the Turkish government will follow developments regarding the incident.

Turkey launched Operation Peace Spring, the third in a series of cross-border anti-terror operations in northern Syria targeting terrorists affiliated with Daesh and the PKK's Syrian offshoot the People's Protection Units (YPG), on October 9 at 4 p.m.

The operation, conducted in line with the country's right to self-defense borne out of international law and U.N. Security Council resolutions, aims to establish a terror-free safe zone for Syrians return in the area east of the Euphrates River controlled by the U.S.-backed Syrian Democratic Forces (SDF), which is dominated by YPG terrorists.

The PKK — listed as a terrorist organization by Turkey, the U.S. and the European Union — has waged a terror campaign against Turkey for more than 30 years, resulting in the deaths of nearly 40,000 people, including women, children and infants.

Turkey has long decried the threat from terrorists east of the Euphrates in northern Syria, pledging military action to prevent the formation of a "terrorist corridor" there.

Since 2016, Turkey's Euphrates Shield and Olive Branch operations in northwestern Syria have liberated the region from YPG/PKK and Daesh terrorists, making it possible for nearly 400,000 Syrians who fled the violence to return home.