A German politician has left the far-right Alternative for Germany to set up a new party with a logo that uses a symbol adopted as a secret sign by Austrian Nazis in the 1930s.

André Poggenburg resigned from his post as the AfD’s regional leader in eastern Saxony-Anhalt state last year after labelling Turks as “camel drivers” and immigrants with dual nationality a “homeless mob we no longer want”. He announced his resignation from the party in an email sent to the leadership earlier this week.

In the email he criticised the AfD for worrying too much about the possibility of being put under surveillance by German intelligence. Separately he told Welt newspaper that he was opposed to a “shift to the left” in the AfD, which has spent the last months ridding itself of extreme elements in an attempt to appear more moderate.

“Unfortunately, the developments inside the AfD in the last weeks and months has shown that it isn’t really my political home any longer,” Poggenburg wrote in the email.

His new party Aufbruch der Deutschen Patrioten (Awakening of German Patriots) will use a German flag against the background of a cornflower. The small blue flower was used as a secret symbol by the then-banned National Socialists in 1930s Austria before the Anschluss of 1938 brought the Nazis to power in the country.

Poggenburg, who has repeatedly come under fire for his use of Nazi-era vocabulary, will bring at least two AfD allies, Egbert Ermer and Benjamin Przybylla, into his fledgling party. The party is said to be planning an electoral debut at regional elections in the eastern states of Saxony, Thuringia and Brandenburg this autumn.

Poggenburg told Welt that he does not want the party to compete with the AfD, and that he proposes “to stay with the successful [political] positioning of the AfD of around two years ago and not go along with the noticeable shift to the left”.

The development will overshadow the AfD’s annual conference in the Saxon town of Riesa, which opened on Friday. Delegates will finalise the party’s programme for upcoming European elections and are expected to reject a proposal supporting “Deuxit” – Germany exiting the EU.

Further distraction came after police released footage of Monday’s violent attack on AfD politician Frank Magnitz. The 66-second CCTV clip appears to show a man striking Magnitz in the head from behind with his bare hand. Magnitz falls to the floor and the man flees, followed by two accomplices.

Police had earlier said the footage cast doubt on the AfD’s account, in which the party claimed unknown assailants knocked Magnitz to the ground with a wooden instrument before beating him around the head. Magnitz, who heads the AfD’s chapter in the city state of Bremen, spent three days in hospital after the attack.

• This article was amended on 12 January 2019 to clarify the description of the logo.