Several people were injured as thousands of far-right protesters rallied Monday in the eastern German city of Chemnitz where a knife killing, allegedly committed by a Syrian and an Iraqi, had sparked racist mob attacks that were deplored by Chancellor Angela Merkel.

Hundreds of riot police separated the noisy crowd - whose mostly male members were chanting slogans against "criminal foreigners" and waving black-red-gold German national flags - from more than 1,000 anti-fascist counter protesters.

Pyrotechnics and other objects hurled from both sides left several people injured and requiring hospital treatment, said police, who moved in water canon and urged the crowds to remain calm.

The right-wing protesters chanted "We are the People" and the Nazi-era term "Luegenpresse" (lying press) and displayed placards that read "Stop the refugee flood" and "Defend Europe", the latter adorned with an image of an automatic rifle.

Some carried banners or insignia of the far-right AfD and neo-Nazi NPD parties and other extremist groups, while a handful delivered the illegal right-handed Hitler salute, said police.