State immunity — Jurisdictional immunity — Customary law obligation to accord immunity — Acta jure imperii and acta jure gestionis — Civil action against State in respect of war crimes and crimes against humanity — Acts having status of acta jure imperii — Territorial tort exception to immunity — Whether applicable to acts of armed forces in conduct of armed conflict — Whether immunity set aside in case of grave illegalities — Jus cogens — Whether immunity available where State accused of violation of jus cogens — Relationship between rule of law violated and rule of law according immunity — Entitlement to immunity determined by law in force at the time action brought — Whether absence of alternative remedy relevant to immunity — United Nations Convention on the Jurisdictional Immunities of States and Their Property, 2004 — Relevance to customary international law

State immunity — Immunity from execution — Property of State in use for non-commercial purposes — Immunity from execution more extensive than immunity from jurisdiction — Proceedings for exequatur to render foreign judgment enforceable in the forum State — Duty of courts of the forum State to determine whether State immunity barred grant of exequatur

States — Sovereign equality of States — State immunity a reflection of principle of sovereign equality of States

Sources of international law — Customary international law — State practice — Customary international law on State immunity — Relevant practice — Judgments of national courts — National legislation — United Nations Convention on the Jurisdictional Immunities of States and Their Property, 2004 — Relevance to customary international law of Convention provisions — Relevance of State comments during negotiation of Convention — State practice in asserting or acknowledging immunity

War and armed conflict — War crimes — Crimes against humanity — Prisoners of war — Occupied territory — Civilian population — Italian armed forces taken prisoner by Germany in 1943 — Denial of status of prisoners of war — Murder and deportation