Iranian President Hassan Rohani has criticized major dam projects by Turkey on the Euphrates and Tigris rivers.
Rohani is demanding that Turkey halt construction of both dams, saying that they were "dangerous" for the entire Middle East.
Rohani made the comments during a conference on sandstorms in Tehran on July 3.
He did not name Turkey but said that multiple dams planned on the two major rivers that flow into Syria and Iraq will have "destructive consequences" and affect many, including Iran.
Turkey's control of the headwaters of the Euphrates and Tigris rivers is controversial in the Middle East.
Critics say decisions made by Turkey have led to water shortages in Syria and Iraq and have contributed to regional instability and wars.
Syrian Kurds in February accused Turkey of cutting off water supplies to the Euphrates River as a form of political pressure.
Activists warn that the dam on the Tigris River at the Turkish village of Ilisu will reduce the water flow to the marshlands of southern Iraq and threaten their existence.