As Germany's anti-immigrant Alternative for Germany (AfD) party seeks to soften its far-right image, party heads ousted Andreas Kalbitz  one of the organization's most influential radical voices.

The AfD's national board said Kalbitz's party membership was annulled over his ties with a now-banned Neo-Nazi youth group. Kalbitz has denied ever being part of the "Heimattreuen Deutschen Jugend" (HDJ) movement but said it was "not unlikely" that his name was on an old HDJ list.

Read more: Germany's AfD seeks 'moderate' path to attract 'middle-class' votes

He was also photographed at an event hosted by the group in 2007 before German authorities declared it illegal two years later.

No former member of HDJ can join AfD under the rules enforced by the party itself. According to the Friday decision, the party leaders rejected Kalbitz's claims he was never in the movement and booted him for "non-disclosure of his membership" in HDJ and a different anti-immigrant party.

Kalbitz to fight decision

The 47-year-old Kalbitz is a close ally of firebrand Björn Höcke. Together, the two held sway in the "Wing," the extremist segment of the party that drew the attention of Germany's domestic intelligence agency. Under pressure from the AfD's executive committee, the "Wing" voted to dissolve itself in March.

On Friday, Kalbitz pledged to "exhaust all legal options" to overrule his expulsion.

Read more: AfD — Radical forces gaining ground

Speaking with public broadcaster ZDF, the head of AfD's parliamentary group and its former co-leader, Alexander Gauland, slammed the decision as "wrong and very dangerous for the party."

The populist AfD has entered the German parliament in 2017 after winning 12.6% of the national vote, but has since seen a slump and is hovering around 9% of support according to April polls.

dj/rc (Reuters, dpa)Every evening, DW sends out a selection of the day's news and features. Sign up here.