the lack of agreement on the legal status of the Caspian Sea between the five littoral states (Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan). The Caspian Sea is the world's largest inland body of water. It is rich in sturgeon, which is harvested for the production of caviar, as well as hydrocarbon reserves, with total oil reserves (proven and possible) at 235.7 billion barrels and gas reserves (proven and possible) at 560 trillion cubic feet, according to the U.S. Energy Information Administration.

Prior to the collapse of the Soviet Union, the Caspian Sea was divided between Iran and the Soviet Union on the basis of the Friendship Treaty of 1921 and the Treaty of Commerce and Navigation of 1940, although it left some issues unresolved such as the protection ofthe local environment and development of resources on the seabed. It also failed to distinguish whether the Caspian was a "sea" or "lake," the former of which would lead to an equidistant division of the body of water under the United Nations Convention on the Law of the Sea while the latter would lead to joint development, characterized as the condominium approach.

Following the Soviet collapse, the six littoral states have adopted differing positions on the status of the Caspian, which have shifted with the growing importance of energy resources in the region. Notably, Russia, Kazakhstan and Azerbaijan have favored sharing the surface waters and dividing the seabed based on the principle of the median line, which has been opposed by Iran and Turkmenistan. Furthermore, Russia has favored a