German authorities are investigating a man suspected of performing the banned Hitler salute during a local party conference of the far-right Alternative for Germany (AfD).

The 26-year-old suspect allegedly made the Nazi gesture while attending the AfD event in the western town of Unna on Sunday.

A participant in a nearby counter-demonstration captured the incident in a photo and reported it to police.

Officers on site then identified the suspect and filed a criminal complaint for the use of symbols of unconstitutional organizations.