Related Rule
United States of America
Practice Relating to Rule 53. Starvation as a Method of Warfare
Section B. Sieges that cause starvation
The US Field Manual (1956), in a chapter dealing, inter alia, with siege warfare, states that, in such a situation, “provision is … made in Article 23 [of the 1949 Geneva Convention IV] for the passage … of essential foodstuffs, clothing, and tonics intended for children under 15, expectant mothers, and maternity cases”. 
United States, Field Manual 27-10, The Law of Land Warfare, US Department of the Army, 18 July 1956, as modified by Change No. 1, 15 July 1976, § 44.