The outcome of the Iraq and Syrian conflicts may rest on who controls the region's dwindling water supplies, say security analysts in London and Baghdad.
Rivers, canals, dams, sewage and desalination plants are now all military targets in the semi-arid region, which regularly experiences extreme water shortages, says Michael Stephen, of the Royal United Services Institute think tank in Qatar.
"Control of water supplies gives strategic control over both cities and countryside," he said. "We are seeing a battle for control of water.
"Water is now the major strategic objective of all groups in Iraq. It's life or death. If you control water in Iraq you have a grip on Baghdad, and you can cause major problems. Water is essential in this conflict."
Jihadist group Islamic State (IS) now controls most of the key upper reaches of the Tigris and Euphrates rivers, which flow from Turkey in the north to the Gulf in the south. All Iraq and much of Syria depend on them for food, water and industry.
"Rebel forces are targeting water installations to cut off supplies to the largely Shia south of Iraq," says Matthew Machowski, a Middle East security researcher.
"It is already being used as an instrument of war. One could claim that controlling water resources in Iraq is even more important than controlling the oil refineries, especially in summer. Control of the water supply is fundamentally important. Cut it off and you create great sanitation and health crises."
Islamic State now controls the Samarra barrage west of Baghdad on the River Tigris and areas around the giant Mosul Dam, higher up on the same river.
Machowski said because much of Kurdistan depended on the dam, it was fiercely defended by Kurdish peshmerga forces and unlikely to fall without a big fight.
Last week Iraqi troops were rushed to defend the massive 8km-long Haditha Dam and its hydroelectric works on the Euphrates to stop it falling into the hands of IS forces. Were the dam to fall, IS would control much of Iraq's electricity and the rebels might fatally tighten their grip on Baghdad.
Securing the Haditha Dam was one of the first objectives of the American special forces invading Iraq in 2003. The fear was that Saddam Hussein's forces could turn the structure that supplies 30 per cent of all Iraq's electricity into a weapon of mass destruction by opening the lock gates that control the river flow.
Billions of litres of water could have been released, power to Baghdad would have been cut, a swathe of towns and villages flooded and the country would have been paralysed.
In April, IS fighters in Fallujah captured the smaller Nuaimiyah Dam on the Euphrates and deliberately diverted its water to "drown" government forces in the surrounding area. Millions of people in Karbala, Najaf, Babylon and Nasiriyah had their water cut off and the town of Abu Ghraib was catastrophically flooded. According to the UN, about 12,000 families lost their homes.
Both IS and the Syrian government have used water widely as a tactical weapon, says Nouar Shamout, a researcher with Chatham House.
"The deliberate targeting of water supply networks . . . is now a daily occurrence in the conflict,' he said. "The water pumping station in Al-Khafsah, Aleppo, stopped working on May 10, cutting off water supply to half of the city. It is unclear who was responsible; both the regime and opposition forces blame each other, but unsurprisingly in a city home to almost three million people the incident caused panic and chaos. Some people even resorted to drinking from puddles in the streets."