ANNEX TO THE CONVENTION : Regulations respecting the laws and customs of war on land #Section IV : On the internment of belligerents and the care of the wounded in neutral countries - Art. 59.
Art. 59. A neutral State may authorize the passage over its territory of wounded or sick belonging to the belligerent armies, on condition that the trains bringing them shall carry neither combatants nor war material. In such a case, the neutral State is bound to adopt such measures of safety and control as may be necessary for the purpose.
Wounded and sick brought under these conditions into neutral territory by one of the belligerents, and belonging to the hostile party, must be guarded by the neutral State, so as to insure their not taking part again in the military operations. The same duty shall devolve on the neutral State with regard to wounded or sick of the other army who may be committed to its care.