A/HRC/31/66 52. The principle of precaution requires that all feasible steps be taken in planning, preparing, and conducting an operation related to an assembly to avoid the use of force or, where force is unavoidable, to minimize its harmful consequences. Even if the use of force in a particular situation complies with the requirements of necessity and proportionality, but the need to use force could reasonably have been prevented from arising in the first place, a State may be held accountable for a failure to take due precautionary measures. 36 Training should include techniques of crowd facilitation and management consonant with the legal framework governing assemblies. 37 States must ensure that their law enforcement officials are periodically trained in and tested on the lawful use of force, and on the use of the weapons with which they are equipped.38 53. On the basis of a risk assessment, equipment for law enforcement officials deployed during assemblies should include both appropriate personal protective equipment and appropriate less-lethal weapons.39 Weapons and tactics should allow for a graduated response and de-escalation of tensions. Accordingly, the provision of a firearm to law enforcement officials with no less-lethal alternative other than a baton is unacceptable. 54. Where necessary, officials must be appropriately protected with equipment, such as shields, helmets and stab- and/or bulletproof jackets, with a view to decreasing the need for any use of weapons by law enforcement. Equipment and weapons that cannot achieve a legitimate law enforcement objective or which present unwarranted risks, particularly in the circumstances of an assembly, should not be authorized for use.40 55. States are required to procure less lethal weapons for use in appropriate situations, with a view to increasingly restraining the application of means capable of causing death or injury.41 Less-lethal weapons must be subject to independent scientific testing and approval, and used responsibly by well-trained law enforcement officials, as such weapons may have lethal or injurious effects if not used correctly or in compliance with international law and human rights standards. States should work to establish and implement international protocols for the training on and use of less-lethal weapons. 56. A growing range of weapons that are remote controlled are becoming available, particularly in the context of the policing of assemblies. Great caution should be exercised in this regard. Where advanced technology is employed, law enforcement officials must, at all times, remain personally in control of the actual delivery or release of force (see A/69/265, paras. 77-87).42 57. The use of force by law enforcement officials should be exceptional, 43 and assemblies should ordinarily be managed with no resort to force. Any use of force must comply with the principles of necessity and proportionality. The necessity requirement restricts the kind and degree of force used to the minimum necessary in the circumstances (the least harmful means available), which is a factual cause and effect assessment. Any force used should be targeted at individuals using violence or to avert an imminent threat. 36 37 38 39 40 41 42 43 European Court of Human Rights, McCann and Others v. United Kingdom, application No. 18984/91, 27 September 1995. Principle 20 of the Basic Principles, and OSCE/ODIHR, Guidelines, para. 147. Principle 19 of the Basic Principles. Principle 2 of the Basic Principles. Less-lethal weapons may still have lethal consequences or affect bystanders (see principle 3 of the Basic Principles). See Amnesty International, Use of Force Guidelines, chap. 6. Ibid. See also African Commission on Human and Peoples’ Rights, general comment No. 3 (2015) on the African Charter on Human and Peoples’ Rights: the right to life (article 4), para. 31. See the commentary to article 3 of the Code of Conduct for Law Enforcement Officials. 13