Соответствующая норма
United States of America
Practice Relating to Rule 1. The Principle of Distinction between Civilians and Combatants
Section B. Attacks against combatants
The US Rules of Engagement for Operation Desert Storm (1991) sets as a basic rule “fight only combatants”. 
United States, Desert Storm – Rules of Engagement, Pocket Card, US Central Command, January 1991, reprinted in Operational Law Handbook, International and Operational Law Department, The Judge Advocate General’s School, United States Army, Charlottesville, Virginia, 1995, pp. 8-7 and 8-8, § 1.
The US Naval Handbook (1995) states that only attacks against combatants and other military objectives are lawful. 
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), § 8.1.
The US Naval Handbook (2007) states: “Only military objectives may be attacked. Military objectives are combatants … ”. 
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, § 8.2.
The Handbook also states: “Lawful combatants … are subject to attack at anytime during hostilities unless they are hors de combat.” 
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, § 8.2.1.
At the CDDH, the United States stated that the first sentence of Article 47(2) of the draft Additional Protocol I (now Article 52(2)) “prohibits only such attacks as may be directed against non-military objectives. It does not deal with the question of collateral damage caused by attacks directed against military objectives.” 
United States, Statement at the CDDH, Official Records, Vol. VI, CDDH/SR.41, 26 May 1977, p. 204.
In March 2010, in a speech given at the Annual Meeting of the American Society of International Law, the Legal Adviser of the US State Department stated:
Recently, a number of legal objections have been raised against U.S. targeting practices. …
First, some have suggested that the very act of targeting a particular leader of an enemy force in an armed conflict must violate the laws of war. But individuals who are part of such an armed group are belligerents and, therefore, lawful targets under international law. During World War II, for example, American aviators tracked and shot down the airplane carrying the architect of the Japanese attack on Pearl Harbor, who was also the leader of enemy forces in the Battle of Midway. This was a lawful operation then, and would be if conducted today. Indeed, targeting particular individuals serves to narrow the focus when force is employed and to avoid broader harm to civilians and civilian objects. 
United States, ‘The Obama Administration and International Law’, Speech by the Legal Adviser of the US Department of State, given at the Annual Meeting of the American Society of International Law, Washington DC, 25 March 2010.
[emphasis in original]