Related Rule
Ukraine
Practice Relating to Rule 27. Religious Personnel
Ukraine’s IHL Manual (2004) states that religious personnel are “protected under international humanitarian law” and that directing attacks against such persons constitutes “a serious violation of international humanitarian law”. 
Ukraine, Manual on the Application of IHL Rules, Ministry of Defence, 11 September 2004, §§ 1.2.33 and 1.8.5.
The manual further states:
1.2.24. Non-combatants (those who do not fight) are members of the armed forces who provide assistance to them but take no direct part in hostilities. These [include] chaplains … Weapons shall not be employed against such persons while they are engaged in the performance of their direct duties.
Such persons become combatants in case of their direct participation in hostilities.
1.2.36. “Religious personnel” means persons who are exclusively engaged in the performance of religious (spiritual) functions. 
Ukraine, Manual on the Application of IHL Rules, Ministry of Defence, 11 September 2004, §§ 1.2.24 and 1.2.36.