International human rights law and international humanitarian law are parallel and complementary branches of international law with their distinct and distinctive supervision arrangements. In the conflicts taking place in the world today, both the institutions of international humanitarian law and international human rights law are called upon to apply and uphold international humanitarian law. The International Committee of the Red Cross has the lead responsibility internationally for watching over the implementation of international humanitarian law, while the United Nations High Commissioner for Human Rights, the Commission on Human Rights, its subsidiary bodies, and the human rights treaty bodies have the lead responsibility for overseeing the implementation of international human rights law. Basic human rights are being violated on a widespread scale during armed conflicts, and international human rights law operates in parallel alongside international humanitarian law in situations of armed conflict. Violations of international humanitarian law, especially as regards civilians, women and children, are violations of basic human rights with which the High Commissioner for Human Rights must be concerned as part of her responsibilities for the worldwide promotion and protection of human rights. Situations may arise increasingly when a High Commissioner for Human Rights is called upon to react to human rights violations in situations of armed conflict. In such situations, a High Commissioner is perforce required to address violations of international humanitarian law. This calls for the exercise of care and discernment on the part of the High Commissioner. Situations must be handled on the basis of principles, first of international humanitarian law, second of international human rights law, and principles of coexistence regarding institutions of international humanitarian law and international human rights law. Specifically, it is fundamental that the High Commissioner be cognizant of and act in the spirit of the principles pervading international humanitarian law. Generally, it is imperative upon a High Commissioner to help discharge the duty of protection and the responsibility to protect.