A/HRC/40/49 supporting the country in their implementation. During the current reporting period, the Special Representative submitted contributions to the universal periodic reviews of Afghanistan, the Central African Republic, the Democratic Republic of the Congo, Nigeria and Yemen. 55. The Special Representative pursued engagement with the special procedures of the Human Rights Council to exchange information and identify common areas of concern. In March 2018, she met with the Special Rapporteur on the sale and sexual exploitation of children, including prostitution, child pornography and other child sexual abuse material and discussed the coordination of advocacy messages. In October 2018, she met with the Special Rapporteur on the human rights of internally displaced persons. They agreed to cooperate closely on the Special Rapporteur’s upcoming report on children internally displaced by armed conflict and other situations of violence. The Special Representative also engaged with the Working Group on the use of mercenaries as a means of violating human rights and impeding the exercise of the right of peoples to self-determination. She is encouraged that the most recent report of the Working Group (A/HRC/39/49 and Corr.1) focused on the recruitment of children by non-State armed groups, including mercenaries and private military and security companies, and welcomes its important recommendations. 56. The Committee on the Rights of the Child and the Human Rights Committee continued to raise the situation of children affected by armed conflict in the national implementation reviews of the Convention on the Rights of the Child and the International Covenant on Civil and Political Rights, respectively. In that regard, the Special Representative took note of the concluding observations of the Committee on the Rights of the Child on the report submitted by Saudi Arabia under article 8 (1) of the Optional Protocol to the Convention on the Rights of the Child on the involvement of children in armed conflict (CRC/C/OPAC/SAU/CO/1). The Committee on the Rights of the Child in its observations urged Saudi Arabia, inter alia, to prioritize the protection of children in all military operations in Yemen, to take concrete and firm precautionary measures and to ensure observance of the core humanitarian law principles, including through a more effective child protection unit. Moving forward, the Special Representative will continue her cooperation with Saudi Arabia and all other members of the coalition to provide support for the swift implementation of the recommendations of the Committee on the Rights of the Child. In its concluding observations on the fourth periodic report of the Democratic Republic of the Congo, the Human Rights Committee reiterated its concerns about children and armed conflict, such as the importance of criminalizing child recruitment and use and facilitating birth registration (CCPR/C/COD/CO/4). The Office of the Special Representative will continue working with United Nations colleagues in the Democratic Republic of the Congo to provide support for the swift implementation of those recommendations. 57. Regarding the global study on children deprived of liberty, the Office of the Special Representative continued to provide data, information and recommendations through its participation in the thematic research group on children deprived of liberty related to armed conflict and children deprived of liberty related to national security. 58. Within the United Nations system, OHCHR continued to be an important partner for the Special Representative, including through its field level participation in the monitoring and reporting mechanisms. The Office of the Special Representative actively participated in the review group on the human rights due diligence policy on United Nations support to non-United Nations security forces, with children and armed conflict concerns being a key component of the policy. The Special Representative also cooperated with OHCHR to include strong child protection elements in the human rights and international law compliance framework of the Joint Force of the Group of Five for the Sahel. Child protection provisions include the appointment of child protection focal points, the issuance of command orders and the adoption of protocols to hand over children to civilian child protection actors. The Special Representative pursued her advocacy, with the support of the Security Council Working Group on Children and Armed Conflict, for the deployment of a child protection adviser to the headquarters of the Joint Force to advise the Force Commander on child protection issues, ensure the mainstreaming of child protection within 15