Related Rule
United States of America
Practice Relating to Rule 60. Improper Use of the United Nations Emblem or Uniform
The US Air Force Pamphlet (1976) provides that it is “forbidden to make improper use of … the distinctive sign of the United Nations”. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 8-3(c).
The Pamphlet further insists that “prohibitions concerning improper use of its [the UN] distinctive signs, emblems and signals should be observed”. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 8-6(b).
The US Naval Handbook (1995) states: “The flag of the United Nations and the letters ‘UN’ may not be used in armed conflict for any purpose without the authorization of the United Nations.” 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 12.4.
The US Naval Handbook (2007) states: “The flag of the United Nations and the letters ‘UN’ may not be used in armed conflict for any purpose without the authorization of the United Nations.” 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 12.4.
In 1987, the Deputy Legal Adviser of the US Department of State affirmed: “We support the principle … that internationally recognized protective emblems … not be improperly used.” 
United States, Remarks of Michael J. Matheson, Deputy Legal Adviser, US Department of State, The Sixth Annual American Red Cross-Washington College of Law Conference on International Humanitarian Law: A Workshop on Customary International Law and the 1977 Protocols Additional to the 1949 Geneva Conventions, American University Journal of International Law and Policy, Vol. 2, 1987, p. 425.