Related Rule
Netherlands
Practice Relating to Rule 32. Humanitarian Relief Objects
The Military Manual (2005) of the Netherlands states:
It is prohibited deliberately to direct attacks against personnel, equipment, units or vehicles involved in the provision of humanitarian aid or peace missions under the UN Charter, provided that they are entitled to the protection afforded under international law to civilians or civilian objects. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 1068.
The Definition of War Crimes Decree (1946) of the Netherlands includes “destruction of relief ships” in its list of war crimes. 
Netherlands, Definition of War Crimes Decree, 1946, Article 1.
Under the International Crimes Act (2003) of the Netherlands, “intentionally directing attacks against … installations, material, units or vehicles involved in humanitarian assistance …, as long as they are entitled to the protection given to … civilian objects under the international law of armed conflict” is a crime, whether committed in an international or a non-international armed conflict. 
Netherlands, International Crimes Act, 2003, Articles 5(5)(o) and 6(3)(c).