Related Rule
Austria
Practice Relating to Rule 161. International Cooperation in Criminal Proceedings
Section C. Extradition of own nationals
In 1968, during a debate in the Third Committee of the UN General Assembly on the question of the punishment of war criminals and of persons who have committed crimes against humanity, Austria stated that “it was a principle recognized in international law that States were not bound to consent to the extradition of their own nationals”. 
Austria, Statement before the Third Committee of the UN General Assembly, UN Doc. A/C.3/SR.1570, 14 October 1968, § 22.