相关规则
Nigeria
Practice Relating to Rule 67. Inviolability of Parlementaires
Nigeria’s Manual on the Laws of War provides:
The parlementaire must carry a white flag while advancing towards the enemy lines thus he and his party will have the privilege of immunity. Nevertheless, in order to prevent unnecessary dangers, the parlementaire should choose a safe and convenient route of approach to the enemy. 
Nigeria, The Laws of War, by Lt. Col. L. Ode PSC, Nigerian Army, Lagos, undated, § 24.
The manual also states that “firing on a white flag” is a war crime. 
Nigeria, The Laws of War, by Lt. Col. L. Ode PSC, Nigerian Army, Lagos, undated, § 6.