3 ( b ) Ensure that firearms are used only in appropriate circumstances and in a manner likely to decrease the risk of unnecessary harm; ( c ) Prohibit the use of those firearms and ammunition that cause unwarranted injury or present an unwarranted risk; ( d ) Regulate the control, storage and issuing of firearms, including procedures for ensuring that law enforcement officials are accountable for the firearms and ammunition issued to them; ( e ) Provide for warnings to be given, if appropriate, when firearms are to be discharged; ( f ) Provide for a system of reporting whenever law enforcement officials use firearms in the performance of their duty. Policing unlawful assemblies 12. As everyone is allowed to participate in lawful and peaceful assemblies, in accordance with the principles embodied in the Universal Declaration of Human Rights and the International Covenant on Civil and Political Rights, Governments and law enforcement agencies and officials shall recognize that force and firearms may be used only in accordance with principles 13 and 14. 13. In the dispersal of assemblies that are unlawful but non-violent, law enforcement officials shall avoid the use of force or, where that is not practicable, shall restrict such force to the minimum extent necessary. 14. In the dispersal of violent assemblies, law enforcement officials may use firearms only when less dangerous means are not practicable and only to the minimum extent necessary. Law enforcement officials shall not use firearms in such cases, except under the conditions stipulated in principle 9. Policing persons in custody or detention 15. Law enforcement officials, in their relations with persons in custody or detention, shall not use force, except when strictly necessary for the maintenance of security and order within the institution, or when personal safety is threatened. 16. Law enforcement officials, in their relations with persons in custody or detention, shall not use firearms, except in self-defence or in the defence of others against the immediate threat of death or serious injury, or when strictly necessary to prevent the escape of a person in custody or detention presenting the danger referred to in principle 9. 17. The preceding principles are without prejudice to the rights, duties and responsibilities of prison officials, as set out in the Standard Minimum Rules for the Treatment of Prisoners, particularly rules 33, 34 and 54. Qualifications, training and counselling 18. Governments and law enforcement agencies shall ensure that all law enforcement officials are selected by proper screening procedures, have appropriate moral, psychological and physical qualities for the effective exercise of their functions and receive continuous and thorough professional training. Their continued fitness to perform these functions should be subject to periodic review. 19. Governments and law enforcement agencies shall ensure that all law enforcement officials are provided with training and are tested in accordance with appropriate proficiency standards in the use of force. Those law enforcement officials who are required to carry firearms should be authorized to do so only upon completion of special training in their use. 20. In the training of law enforcement officials, Governments and law enforcement agencies shall give special attention to issues of police ethics and human rights, especially in the investigative process, to alternatives to the use of force and firearms, including the peaceful settlement of conflicts, the