A/HRC/34/44 visits. The release of the 26 children follows the handover to child protection actors of over 100 children detained in the Serendi and Hiil-Walaal centres as well as in Galmudug, in late 2015 and in 2016. 24. In the same vein, the Office of the Special Representative has sustained its efforts to improve the principles of protection for children deprived of liberty in situations of armed conflict. In November, in Geneva, the Special Representative attended the twenty-fifth anniversary of the creation of the Working Group on Arbitrary Detention and emphasized the importance of focusing on children in efforts to end arbitrary detention. The Office of the Special Representative also worked closely with the United Nations Office on Drugs and Crime throughout the reporting period, including by providing child protection expertise at two workshops with government officials on the issue of children recruited and used by violent extremist groups, which were held in Amman and Dakar. The Office of the Special Representative also took part in an event in association with the steering group for the principles relating to the status of national institutions for the promotion and protection of human rights (Paris Principles), at Wilton Park, in the United Kingdom of Great Britain and Northern Ireland, on protecting children from extreme violence, which focused on the treatment of those who have been recruited and used. The outcomes of that conference will be used to prepare for an event for the tenth anniversary of the Paris Principles, which will be held in Paris in February 2017. Lastly, the Special Representative also continued to contribute to the initial phase of the in-depth global study on children deprived of liberty, in line with General Assembly resolution 69/157,7 and took part in an event in November in Geneva with the independent expert and lead author of the global study, Manfred Nowak. C. Ending grave violations 25. In the past year, the Special Representative has continued to prioritize interactions with parties to conflict to end grave violations against children. However, while progress has been forthcoming, the sheer number and differing nature of actors in armed conflicts has contributed to the creation of an environment where the protection of children is increasingly challenging and resource-intensive. In particular, the multiplicity of non-State armed groups, including militias that are used to fight on behalf of Governments, and the increasing number of military operations carried out by international coalitions, have challenged the child protection community’s ability to prevent and respond to grave violations. The very nature of these actors, with their loose composition and the lack of clarity in their command structures, can hamper advocacy efforts seeking to ensure that fundamental safeguards are implemented, such as precautionary measures and adherence to the principle of distinction. 26. In this regard, one of the most disturbing trends documented in 2016, noted earlier in the present report, is the increasing incidence of attacks on health facilities, which has had a grave impact on children’s right to health. Hospitals, ambulances and medical personnel have been attacked or threatened with attack in many countries that are on the children and armed conflict agenda, including Afghanistan, the Central African Republic, Iraq, Libya, Mali, South Sudan, the Syrian Arab Republic and Yemen. The Special Representative has engaged strongly on this issue with parties to conflict and has taken part in a number of United Nations system-wide initiatives. For example, the Office of the Special Representative has supported the development of recommendations on measures to enhance protection of the wounded and sick and of medical personnel and humanitarian personnel exclusively engaged in medical duties, and of their means of transport and equipment and 7 See para. 52 (d). 9