It is a well-settled principle of international law that the appropriate responses of a coastal state to an intrusion by a foreign submarine into its internal waters or a non-innocent passage through its territorial sea are limited to requiring the intruding ship to leave its waters and to making a protest to the ship's flag state. This norm is related to the international principle of jurisdictional immunity of foreign warships, a principle long deemed vital to the public order of the oceans.
Foreign Submarines in Swedish Waters: The Erosion of an International Norm,
Yale J. Int'l L.
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