Related Rule
Israel
Practice Relating to Rule 20. Advance Warning
Israel’s Manual on the Rules of Warfare (2006) states:
The rules of war have laid down a number of rules of engagement in a theatre of war containing civilians:
- An attempt should be made to move the civilian population away from military targets by distributing leaflets, issuing warnings through loudspeakers, giving sufficient notice of an attack, etc, unless there are overriding, compelling military needs (immediate attack, surprise attack). 
Israel, Rules of Warfare on the Battlefield, Military Advocate-General’s Corps Command, IDF School of Military Law, Second Edition, 2006, p. 27.
The Manual on the Rules of Warfare (2006) is a second edition of the Manual on the Laws of War (1998).
In its judgment in the Adalah (Early Warning Procedure) case in 2005, Israel’s High Court of Justice stated:
An army in an area under belligerent occupation is permitted to arrest local residents wanted by it, who endanger its security (see HCJ 102/82 Tsemel v. The Minister of Defense, 37 (3) PD 365, 369; HCJ 3239/02 Marab v. The Commander of IDF Forces in the Judea and Samaria Area, 57 (2) PD 349, 365). In this framework – and to the extent that it does not frustrate the military action intended to arrest the wanted person, the army is permitted – and at times even required – to give the wanted person an early warning. Thus it is possible to ensure the making of the arrest without injury to the civilian population (see regulation 26 of Regulations Concerning the Laws and Customs of War on Land, The Hague, 18 October 1907 (hereinafter – The Hague Regulations); article 57(2) of Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Protocol I), 8 June 1977 (hereinafter – The First Protocol); see also Fleck The Handbook of Humanitarian Law in Armed Conflicts (1995) 171, 223 (hereinafter – Fleck); rule 20 of 1 Customary International Humanitarian Law: Rules (2005) 62 (hereinafter – International Humanitarian Law)). 
Israel, High Court of Justice, Adalah (Early Warning Procedure) case, Judgment, 6 October 2005, § 20.
In a briefing in 1982, the Israeli Ministry of Foreign Affairs declared that all precautions had been taken by Israeli forces by giving an effective advance warning through the distribution of leaflets and appeals to the civilian population via radio and loudspeakers so that they could leave the operational zone temporarily. 
Israel, Ministry of Foreign Affairs, Department of Information, Briefing 342/18.7.82/3.10.108, 18 July 1982.
On 13 October 2000, Israeli helicopters carried out an air-strike on a Palestinian police station in Ramallah in retaliation for the killing of two Israeli soldiers the previous day. After the attack, a senior Israel Defense Force officer said that the military had made every effort to avoid casualties, warning the Palestinian police to evacuate their posts three hours before the strike. Warning shots were also fired minutes before the actual attack to warn off those who had not understood the earlier message. 
Israel, Press briefing by the Director-General of Science, Culture and Sports, Coordinator of Information Policy and the Head of the IDF Operation Branch, Jerusalem, 13 October 2000; Suzanne Goldenberg, “Israel launches rocket attacks after frantic mob murders soldiers”, The Guardian, 13 October 2000.
The Report on the Practice of Israel states:
The issue of “effective advance warning” is somewhat complicated. Unfortunately, due to current practices in the region, in which attacking forces are shielded within civilian populated localities (especially as regards the activities of the terrorist organizations in Lebanon), Israel is forced, quite often, to return fire at targets situated in close vicinity to civilians. Obviously, issuing advance warning of such counter fire is unfeasible from both military and logical perspectives (not only is time of an essence in such cases, but the civilian population is already all too aware of the fact that hostilities are taking place in their immediate area) … Nevertheless, Israel and the IDF [Israel Defense Forces] have, on several occasions in the past, made public advance warnings to the civilian population in Lebanon of impending hostilities. Such instances include the 1982 operation “Peace for Galilee”, during which the IDF dropped leaflets over cities in the vicinity of which hostilities were expected, thereby enabling those elements of the population uninvolved in the conflict to vacate the area beforehand. Similar practices were adopted by Israel in other Lebanese-related operations over the years … Israel has found that the use of advance warnings to the civilian population is feasible only prior to the commencement of hostilities in a general area, or in cases in which the elements of surprise or speed of response play no significant part. 
Report on the Practice of Israel, 1997, Chapter 1.6.
In 2006, Israel’s Ministry of Foreign Affairs stated:
[W]henever it is possible without jeopardizing the operation, Israel issues advance notice to the local residents through various media, including dropping leaflets, to distance themselves from areas in which Hizballah is operating and from places in which weaponry is stored. 
Israel, Responding to Hizbullah Attacks from Lebanon: Issues of Proportionality, Legal Background, Ministry of Foreign Affairs of Israel, 25 July 2006, § 4.
In 2006, in a statement to the Knesset, Israel’s Minister of Defense stated:
Whenever we intend to target a munitions depot in a building in which a family resides, Israeli Intelligence devotes great effort to find the telephone number of that family, phone them and ask them to leave the house two hours before in order that they not be harmed. 
Israel, Statement by Defense Minister Amir Peretz to the Knesset, 31 July 2006.
In 2007, Israel’s Ministry of Foreign Affairs stated in a diplomatic note:
Finally, whenever possible without jeopardizing the operation, Israel issued advance notice to the local residents through various media, including dropping leaflets, radio broadcasts and contacts with local leaders, to distance themselves from areas in which Hizbullah was operating and from places in which its weaponry was being stored. 
Israel, Israel’s War with Hizbullah. Preserving Humanitarian Principles While Combating Terrorism, Diplomatic Notes No. 1, Ministry of Foreign Affairs of Israel, April 2007, pp. 14-15.
The Ministry further stated:
Despite the urgent need to prevent the continuous firing of missiles into Israel by Hizbullah, Israel recognized the need to take measures to avoid, and in any event to minimize, civilian casualties. Among the measures taken by Israel was the printing of millions of fliers, written in Arabic, which were dispersed over populated areas, explaining that due to Hizbullah activity, residents should evacuate these areas in order to avoid being hurt. These messages were also broadcast through PA systems and through radio broadcasts on the Al-Mashrek station, broadcasting out of Israel in Arabic. Additionally, Israeli officials contacted the mayors and local leaders of a number of villages in order to ensure the evacuation of residents. 
Israel, Israel’s War with Hizbullah. Preserving Humanitarian Principles While Combating Terrorism, Diplomatic Notes No. 1, Ministry of Foreign Affairs of Israel, April 2007, p. 19.
In March 2008, in a briefing to the Diplomatic Corps on Israel’s operations in Gaza, Israel’s Vice Prime Minister and Minister of Foreign Affairs stated:
[W]e decided to avoid civilian casualties by sending a warning message to a place from which we knew the terrorists act. … We prefer to attack an empty building which is being used to manufacture rockets, even taking into consideration that the terrorists will leave the place. 
Israel, Briefing to the Diplomatic Corps by the Vice Prime Minister and Minister of Foreign Affairs, 3 March 2008.
In December 2008, in a briefing to the Diplomatic Corps on Israel’s operations in Gaza, Israel’s Vice Prime Minister and Minister of Foreign Affairs stated:
[B]efore this military operation, we called on the civilians to leave those places that they know are Hamas headquarters or places where Hamas people live or have gathered, in order to attack Israel. … And maybe Israel is the only state in which warnings are given in advance to the civilian population to leave a place that we know we need to target a few minutes later, a few hours later or a few days later. 
Israel, Briefing to the Diplomatic Corps by the Vice Prime Minister and Minister of Foreign Affairs, 28 December 2008.
In 2008, in a background paper on Israel’s operations in Gaza, Israel’s Ministry of Foreign Affairs stated:
[W]here it [is] possible to do so without compromising the effectiveness of an operation, the IDF [Israel Defense Forces] makes strenuous efforts to give advance notice to the civilian population in the vicinity of military targets, including places used by terrorists for storing weapons and launching attacks, so that they have an opportunity to leave the area. The warnings are carried out by means of the dropping of leaflets in Arabic, telephone calls and radio announcements. By encouraging civilians to leave such areas, these means have been found to be effective in saving lives. 
Israel, Ministry of Foreign Affairs, Background paper, Responding to Hamas Attacks from Gaza: Issues of Proportionality, December 2008, § 4.
In 2009, in a report on Israeli operations in Gaza between 27 December 2008 and 18 January 2009 (the “Gaza Operation”, also known as “Operation Cast Lead”), Israel’s Ministry of Foreign Affairs stated:
134. The requirement of effective warnings to the civilian population is also tempered by the express caveat, “unless circumstances do not permit.” The circumstances in question include the effect on achievement of the military mission or the security of the forces …
136. As a stark example, consider an adversary that launches mortars or anti-tank missiles from within civilian areas. There may be no choice except to return fire, even though this creates jeopardy for the civilians in the vicinity. Issuing an advance warning of the counter-fire may also be impractical, because it gives the shooter time to move. For this reason, advance warnings to the civilian population may be feasible mostly before hostilities begin in a particular area, or where the lack of surprise or speed of response does not significantly affect military advantage.
137. In certain circumstances, general warnings might be adequate in order to fulfil the obligations of the parties to an armed conflict under international law. …
210. … IDF [Israel Defense Forces] forces imposed on themselves a multi-faceted system of early warnings, which made their operations far more complex and largely eliminated the element of surprise the IDF might have otherwise gained in its battle against Hamas. In many cases, IDF forces provided not one but multiple warnings prior to each attack and used sophisticated technology to confirm the departure of civilians and minimise collateral damage.
225. The document [operational order] further confirmed the importance of minimising incidental harm to civilians and civilian facilities. The operational order provided that “[a]s far as it is possible under the existing circumstances, civilian population in the vicinity of a legitimate military objective shall be warned before an attack. Such early warning may be avoided, if it would risk the operation or the forces.” 
Israel, Ministry of Foreign Affairs, The Operation in Gaza 27 December 2008–18 January 2009: Factual and Legal Aspects, 29 July 2009, §§ 134, 136–137, 210 and 225.
[footnote in original omitted]
The report also specified a number of the methods employed by the Israel Defense Forces (IDF) to provide advance warning to civilians:
262. The IDF also made special efforts to notify civilians of impending IDF operations and to instruct them how to avoid harm. The early warnings system was comprised of several layers that were complementary to each other.
263. First, general warnings were used, calling on civilians to stay away from sites where Hamas was conducting combat activities. In addition, regional warnings were distributed in certain areas, calling on civilians to leave those areas before IDF forces operated in them. Efforts were made to include in these warnings sufficient information to the residents, including a timeframe for the evacuation and designated specific routes for this purpose leading to safe areas. Far from having no place to flee, residents could – and the vast majority did – move to safe locations. Finally, specific warnings were issued to residents of particular buildings before attack.
264. Throughout the Gaza Operation, the IDF employed a variety of methods to communicate warnings effectively. The warning techniques included:
- Radio Broadcasts and Phone Calls: The IDF conveyed instructions and advance warnings to residents by local radio broadcasts with IDF announcements and by about 165,000 phone calls. This involved specific notices as well as a daily news broadcast (the latter from 31 December onwards).
- Dropping of Leaflets: During the Gaza Operation, the IDF dropped a total of some 2,500,000 leaflets of various kinds in the Gaza Strip. Some of the leaflets warned civilians to distance themselves from military targets, including buildings containing weapons, ammunitions or tunnels, or areas where terrorist activity was being conducted. Other leaflets directed residents to leave a particular location and move to a safe zone by a certain route and within a defined period of time. Such leaflets were distributed, for instance, in the northern Gaza neighbourhood of Sajaiya. While warnings were a significant tool to reduce the likelihood of civilian casualties, IDF forces did not consider the distribution of leaflets alone as sufficient to presume the absence of civilians at the relevant locations.
- Specific Warnings Before Attacks: In addition to the above, the IDF made specific telephone calls just before an attack was about to take place, informing residents at risk about the upcoming strike and urging them to leave the place. In certain instances, although such warnings were made, the civilians chose to stay. In such cases, the IDF made even greater efforts to avoid civilian casualties and minimise collateral damage by firing warning shots from light weapons that hit the roofs of the designated targets, before proceeding with the strike. These warnings were accompanied by real-time surveillance in order to assess the presence of civilians in the designated military target, despite the advance warnings. Accordingly, the commander in charge assessed whether the collateral damage anticipated, including to those who chose to stay at the premises, was not excessive in relation to the military advantage anticipated. The specific warnings were generally effective. Several such incidents are discussed …
265. While the warning systems implemented by the IDF did not provide a 100 per cent guarantee against civilian casualties, they were, in fact, highly effective. Aerial video surveillance by IDF forces confirmed the departure of civilians from targeted areas prior to the attack as a direct result of the warnings. 
Israel, Ministry of Foreign Affairs, The Operation in Gaza 27 December 2008–18 January 2009: Factual and Legal Aspects, 29 July 2009, §§ 262–265.
[emphasis in original; footnotes in original omitted]