But marches by "violence-prone right-wing extremists and neo-Nazis have nothing in the least to do with mourning for a person or with concern for a city's cohesion", he said.
Opperman argued that violent demonstrations in Chemnitz had hereby showcased how the AfD cooperated with Neonazis and other far-right activists who were plotting to overthrow Germany's constitutional order.
Tens of thousands of people gathered in Chemnitz on Monday for a free, open-air concert by some of Germany's best-known bands.
Numerous far-right supporters came from the anti-immigrant Alternative for Germany (AfD) party, and the anti-Islam Populist Europeans Against the Islamisation of the West (PEGIDA) movement, according to police.
We will remind, in the German city of Chemnitz during demonstrations for and against the acceptance of refugees, the police arrested 300 people in the riots were injured dozens of protesters.
On Sunday, Foreign Minister Heiko Maas urged Germans to "get off our sofas and open our mouths" against xenophobia.
Soon after, dozens of far-right protesters ignored police orders to stay put and made their way past a line of police cars blocking a major street in the city centre to prevent the rival marches from crossing paths.
"We're not naive. We're not laboring under the illusion that you hold a concert and the world is saved", the singer of Kraftklub, Felix Brummer, said ahead of the concert.
Authorities in Bremen and Lower Saxony said they have begun monitoring the party's youth wings in those two northern states.
Previously, the AfD has been keen to distance itself from Pegida, but observers say it has been emboldened by the boost in support it has received since the recent clashes, in which far-right supporters raised their arms in illegal Nazi salutes, and immigrants were chased through the streets of Chemnitz.
Two suspects have been arrested and face manslaughter charges in the stabbing death of 35-year-old Daniel Hillig, whose portrait was carried during a September 1 procession organized by the right-wing party Alternative for Germany (AfD).
Germany has seen the influx of more than 1.6 million asylum seekers in the past four years, mainly Muslims from Syria, Iraq, and Afghanistan, triggering fears that mass migration might undercut social stability.
Abdul D, believed to be Afghan, admitted stabbing Mia V in December in the south-western town of Kandel.
Because of privacy rules, the victim in the Kandel stabbing has been identified only as Mia and the migrant as Abdul D., who was also convicted of assault at the district court in Landau.
Surveys suggest it is poised to become Saxony's second biggest party in next year's regional elections. Prosecutors claimed during the trial that the migrant acted out of jealously and revenge and that he wanted to punish her. Police said they were investigating if the perpetrators counted among demonstrators.
Several demonstrators openly did the Hitler salute - a criminal offense in Germany - leading to nationwide debates about the strength and degree of influence of the far-right, especially in the east.
Rhineland-Palatinate state premier Malu Dreyer accused the far-right of exploiting the teenager's death for political gains, saying this was "intolerable".
Defending champion Stephens knocked out of US Open last eight by Sevastova
Stephens said that despite the manner of her defeat on Tuesday she was content with what she had achieved at this tournament. I am not happy about this, ' he said, managing a smile. 'And obviously defending a title is very hard, very difficult.