Speaking before the U.N. Security Council Monday, U.N. High Commissioner for Refugees António Guterres said people who reject Syrian refugees are the “best allies” of extremists like the self-proclaimed Islamic State.

António Guterres: “Those that reject Syrian refugees, and especially if they are Muslim, are the best allies of the propaganda and the recruitment of extremist groups. We must not forget that—despite the rhetoric we are hearing these days—refugees are the first victims of such terror, not its source. They cannot be blamed for a threat which they’re risking their lives to escape.”