Which UN mechanism or official may warn a state regarding conditions that could amount to inhuman or degrading treatment of a prisoner?

💡 Explanation:

United Nations Special Rapporteurs are independent experts appointed by the Human Rights Council to investigate and report on a country's situation or a specific human rights theme. They are a critical part of the UN's 'Special Procedures' and issue urgent appeals or warnings on human rights violations, such as detention conditions that may violate international norms like the Convention Against Torture.