A video has emerged showing Germany’s vice-chancellor giving the middle finger to a group of neo-Nazi protesters who had called the politician a “race traitor”.

The clip, filmed last Friday but posted on social media on Tuesday, shows a group of about 20 men in Germany flag masks interrupting an election campaign event in Salzgitter, Lower Saxony, involving the Social Democrat politician Sigmar Gabriel.

The protesters can be heard calling the centre-left politician a “communist and cultural Marxist”, as well as making a reference to Gabriel’s father, a Nazi sympathiser: “Your father loved his country, and what do you do? You destroy it.”

The deputy to the German chancellor, Angela Merkel, is then seen laughing before raising his middle finger and turning his back on the group.

In an interview about his upbringing published before the 2013 federal elections, Gabriel had revealed that he broke off contact with his father after discovering his Nazi beliefs when he was 18. In the interview, Gabriel said: “What remains is an almost untameable anger. When I see something unfair, when injustice is being done to people, I can get properly worked up.”

According to local media, after the incident shown on the video Gabriel had invited the protesters for a discussion under the condition that they would take off their masks.However, the group declined and then dispersed. Eleven of the protesters were later stopped by police and banned from the premises.

Facebook Twitter Pinterest Sigmar Gabriel with the German chancellor, Angela Merkel. Photograph: Odd Andersen/AFP/Getty Images

Gabriel has become a hate figure for the country’s far right for his supportive stance towards Merkel’s open-borders stance during the refugee crisis. Last summer, his party received bomb threats and hate mail after Gabriel vocally dismissed as a “mob” the people behind anti-refugee riots in the town of Heidenau near Dresden.

The branding on the original version of the video shared on social media indicates that the protest was organised by the Young National Democrats, the official youth branch of the NPD, a far-right party that Germany’s constitutional court could potentially ban this autumn.

Merkel is bracing herself for a similar response as she joins her party’s campaign trail in Mecklenburg-Vorpommern, where local elections are taking place on 4 September. During a visit to the town of Stralsund in February, the chancellor was met with chants of “Merkel has to go”.