Far-right
Merkel's decision in 2015 to let in about a million migrants, many fleeing wars in the Middle East, has fueled support for far-right groups such as PEGIDA and the Alternative for Germany (AfD), now the main opposition party in parliament.
Tweeting about Sunday's incident, AfD politician Markus Frohnmaier said: "If the state is no longer to protect citizens then people take to the streets and protect themselves. It's as simple as that!"
Martina Renner, a lawmaker for the radical Left party, accused the far-right of trying to exploit a murder for its own political ends. "A terrible murder, the background to which is still unclear, is being instrumentalised in the most repugnant way for racist riots in Chemnitz," she tweeted.
The violence in Chemnitz is likely to put further pressure on Merkel's conservatives, who last week faced accusations of ignoring the rise of far-right groups in the eastern state of Saxony, where Chemnitz lies.
Police in Chemnitz are preparing for further demonstrations. They were expected to issue a further statement about Sunday's incident later on Monday.