BERLIN (AP) — German authorities say protests in the eastern city of Chemnitz this week were fueled by unsubstantiated claims that the victim of a fatal stabbing was protecting a woman from harassment by migrants.

A picture widely shared on social media urged people to attend a march in the city Monday to "commemorate the courageous person who lost his life trying to protect a woman."

Chemnitz prosecutors' spokeswoman Ingrid Burghart said Wednesday "there is absolutely no evidence that harassment was a reason for this dispute," in which a German man was killed.

A 22-year-old Syrian and a 21-year-old Iraqi were arrested on suspicion of manslaughter in connection with the killing.

At least 18 people were injured when far-right extremists attending the protest clashed with counter-demonstrators, as police tried to separate the sides.