After President Donald Trump floated on Monday the possibility of expanding the Iran war by potentially striking water treatment plants in Iran, some Persian Gulf Arab countries reiterated grave concerns to the Trump administration about any strikes on civilian infrastructure and the risk of an intensifying tit-for-tat escalation, according to four regional sources.

Civilian infrastructure sites like water plants are clearly banned as targets by international law. If Iran responded to a U.S. strike on a water plant by hitting a similar facility in a nearby country, it could trigger devastating consequences. 

“It will be a huge catastrophe if they strike, we rely on desalination for almost all drinking water,” said one regional official, explaining that the concerns about pursuing these strikes have been clearly articulated to Trump administration officials in the past and were reiterated after Trump’s Truth Social post on Monday. 

While several countries have privately reached out to the Trump administration to warn against such attacks, they’ve so far avoided publicly rebuking the U.S. president. 

Targeting critical civilian infrastructure, which includes water plants and potentially power plants that have also been the subject of Trump threats, could be considered a war crime. The Geneva Conventions and its protocols define objects indispensable to the survival of a civilian population as illegal military targets, and clearly cites “drinking water installations and supplies and irrigation work” as falling into that category. 

“Desalination plants are purely civilian infrastructure. There is no legal argument whatsoever for attacking them,” said Kenneth Roth, a former executive director of Human Rights Watch, adding that those advising Trump have “a responsibility not to implement any illegal order.” 

Iran gets only a small fraction of its water from desalination plants. But nearby countries including Qatar and Bahrain produce more than half of their drinking water using the technology, which converts seawater into potable water by removing the salt.