Turkish police detained leaders of a Russia-based North Korea friendship group over an anti-NATO protest ahead of the alliance’s summit this week as part of the government’s sweeping efforts against alleged political extremists.

The arrests Wednesday morning targeted around 20 participants of an event organized by the World Anti-imperialist Youth Platform in the western Turkish city of Çanakkale, southwest of Istanbul, according to the international political group uniting left-wing organizations.

Among those detained were Alexander Mostov, the former head and current member of the Moscow-based DPRK International Solidarity Group (ISG), and ISG executive committee chief Daria Kadkina, according to an