24 other participants. This may enable the main assembly to continue.77 If these targeted interventions are ineffective, law enforcement officials may employ weapons that target groups rather than individuals (such as water cannon or tear gas) after having issued an appropriate warning, unless giving the warning would cause a delay that would either risk causing serious injury or, in the circumstances, be futile. In addition, participants in the assembly should be given time to obey the warning and a safe space or route for them to move to shall be ensured. 6.3.4 The use of firearms to disperse an assembly is always unlawful. In situations where some force is necessary, only less-lethal weapons may be used. In such situations, less-lethal weapons that can be individually aimed shall target only individuals engaged in acts of violence. Weapons such as chemical irritants dispersed at a distance (tear gas) should be targeted at groups of violent individuals unless it is lawful in the circumstances to disperse the entire assembly. Such use should accord due consideration to the impact on other non-violent participants or bystanders. In addition, when the use of any less-lethal weapons or related equipment against assembly participants is envisaged, due attention should be paid to the potential for panic in a crowd, including the risk of a stampede. Only weapons that meet international standards of accuracy may be used. 6.3.5 Physical barriers should never be such as to pose a risk to safety. Barbed wire, razor wire or other spiked barriers typically create an undue risk of injury to participants in an assembly. Where a barrier is needed, safer alternatives should be employed. 6.3.6 Medical personnel, whether they are acting officially or as volunteers, should be provided with safe access to attend to any injured individuals. 77 Joint report of the Special Rapporteur on the rights to freedom of peaceful assembly and of association and the Special Rapporteur on extrajudicial, summary or arbitrary executions on the proper management of assemblies (A/HRC/31/66), para. 52. See also Human Rights Council resolution 25/38, para. 9.