Water supplies are increasingly being targeted during armed conflicts. Since it invaded Ukraine last month, Russia has cut off the water supply to the besieged city of Mariupol to drive it to surrender. It has also destroyed a canal dam that Ukraine constructed in 2014 to control the water supply into Crimea after Russia annexed the peninsula.

Water resources and infrastructure have been attacked in other conflicts. In 2014, the Islamist terrorist group ISIS cut off water to Mosul in northern Iraq and threatened to use the dam there to flood Baghdad. Also in 2014, Syrian government forces targeted the country’s ISIS-controlled water plant in Raqqa and, in 2016, they attacked the Fijeh Spring in the besieged Wadi Barada valley (M. Daoudy Int. Affairs 96, 1347–1366; 2020).

It is imperative that international humanitarian law be respected in relation to fresh-water supplies. The Geneva List of Principles on the Protection of Water Infrastructure sets out international rules for application during armed conflicts and makes valuable recommendations that go beyond existing law (see go.nature.com/3nnznww). Attempts to override these protective mechanisms should not be tolerated.