Around 15 members of the group "Identity Movement" climbed the Brandenburg Gate on Saturday before hanging two banners from the landmark's horse-drawn chariot statue. The larger of the two read: "Secure borders - secure future," while the second displayed the group's name.

Counter-protesters quickly gathered on Pariser Platz in front of the gate, chanting slogans such as "Nazis out!"

The right-wing activists climbed down about an hour later after police demands. According to comments on the group's Facebook page, they coordinated the stunt with an open day of government buildings centered on the topic of "Migration and integration."

Group under surveillance

Berlin's Interior Minister Frank Henkel and the city's mayor Michael Müller strongly condemned the protest.

"It is simply disgusting that with this kind of action the enemies of democracy are trying to appropriate a symbol that stands for a democratic, free and open Germany," Müller said.

Active since 2012, the "Identity Movement" is radically opposed to foreign and Islamic influence in Germany.

The group is currently being monitored by Germany's intelligence services for alleged efforts to undermine civil liberties.