People take part in a gathering organized by the right-wing Alternative for Germany to commemorate the death of a Chemnitz man on September 1, 2018. Two men, a Syrian and an Iraqi, are accused of having stabbed him following an altercation. (Photo by Jens Schlueter/Getty Images)

(Update: Corrects spelling of Bill Wirtz of Young Voices)

Berlin (CNSNews.com) – Liberal German politicians are calling for government surveillance of the far-right Alternative für Deutschland (AfD) party, after some members marched alongside neo-Nazis during an anti-immigrant rally in the eastern city of Chemnitz.

“Germany’s domestic intelligence service must investigate the collaboration between the AfD and neo-Nazis very closely,” the vice president of the Bundestag, Thomas Oppermann of the center-left Social Democrats (SPD), said in an interview on Monday.

“The refugee debate is dividing our society and the AfD is riding this wave more radically than ever,” he said.

Protests broke out in Chemnitz after two men – an Iraqi and a Syrian – were arrested on suspicion of fatally stabbing a German man. Protest participants included neo-Nazis and supporters of the anti-Islam activist group Pegida, with some protesting chanting “foreigners out,” making straight-arm “Hitler salutes” – which are banned in Germany – and clashing with left-wing counter protestors.

Federal lawmaker Cem Özdemir, a former leader of the Greens, said monitoring the AfD was now necessary in order to examine possible links to extremist groups.

“You would finally have reliable information about which networks the party maintains and how it finances itself,” he told German media.

“Politically, Chancellor [Angela] Merkel is boxed into a corner particularly because the AfD as the third largest party in parliament, is no longer an insignificant outlier," said Albert Goldson, executive director of New York-based Indo-Brazilian Associates LLC, which provides geopolitical risk assessment.

If left unchecked, Goldson warned, AfD members openly supporting extremists could prompt a violent trend throughout Germany, forcing the government to apply aggressive law enforcement tactics beyond surveillance, which in turn could destabilize the government.

A poll Monday found that 57 percent of Germans agree that the AfD should be monitored.

At the same time, however, popular opinion of the party improved following the killing and the protests: The AfD rose two percentage points to 16 percent in an Insa opinion poll on Monday, edging ahead of the SPD – a member of Merkel’s coalition government.

The SPD stood at 16 percent in the poll, while Merkel’s center-right bloc led with 28.5 percent.

Bill Wirtz of Young Voices, a nonprofit public relations organization, cautioned that putting the AfD under surveillance sends the wrong message.

“The implication that they endanger the German constitution will only embolden their supporters in the belief that they are being unjustly persecuted,” he said.

“If liberal democracy wants to survive, it needs to use the tools that it purports to defend: free speech, open dialogue, and the rule of law,” he said. Wirtz recalled the authorities’ attempt to deal a spate of sexual assaults in Cologne on New Year’s Eve 2015 by downplaying the attacks – which were largely blamed on foreigners.

The AfD entered the federal parliament for the first time last year winning 13 percent of the vote, riding on a wave of unease over the influx of more than one million migrants and refugees since 2015.

The party has courted controversy numerous times – for instance last January when Bjorn Höcke, head of the party’s Thuringia branch, called Berlin’s Holocaust memorial a “monument of shame,” or an incident last year when party co-leader Alexander Gauland said Germans should be proud of Nazis’ military achievements.

Reacting to calls to monitor his party, chairman Joerg Meuthen said during comments at a community festival, “The country has clearly gone mad.”

Meuthen said the government should instead be monitoring far-left rock bands which organized a counter-demonstration concert in Chemnitz on Monday. . One of the bands involved is known for lyrics that refer to street violence and hurling stones at police, It was under regional surveillance from 2012 to 2015.

Merkel has refrained from commenting directly on the tensions, saying instead it was up to the state security agency to decide on monitoring decisions, and not a matter of politics.

However, Olaf Scholz, her SPD finance minister, said although he agreed with Merkel, the clashes in Chemnitz gave clear cause for a renewed look at whether the AfD should be monitored.

State surveillance is a historically sensitive topic in Germany due to memories of the Nazi and communist eras. But the constitution also contains rules allowing surveillance of extremist groups, to prevent them from growing too powerful.

Two AfD state youth wings were formally placed under surveillance on Monday over suspected connections to the white nationalist “Identitarian” movement. The party immediately announced plans to dissolve the two groups.

Some members of the socialist Linke (Left) party, have been subject to state surveillance in the past.