Syria’s government urged U.N. Secretary-General Antonio Guterres to demand that a U.S.-led military campaign against Islamic State militants stop targeting the Euphrates and Tishrin dams and surrounding areas “to forestall a looming catastrophe.”

In a letter to Guterres and the Security Council, released on Thursday, Syria’s Deputy U.N. Ambassador Mounzer Mounzer wrote that residents along the Euphrates River in Iraq could also be affected by the “systematic sabotage of infrastructure.”

“The total destruction of these dams that are being targeted by the air strikes will wash away and flood cities, towns and villages, endangering the lives of hundreds of thousands of people living in those areas,” Mounzer wrote.

The international coalition and the Pentagon were not immediately available for comment. The U.S.-led coalition has been carrying out air strikes in Syria against Islamic State militants since September 2014.