Foreign Ministry spokesman Bahram Qassemi on Saturday announced that the foreign ministers of the five Caspian Sea littoral states, including Iran, are scheduled to take part in the fifth Caspian Sea summit in Kazakhstan on Sunday to adopt a convention on its legal status, IRIB reported.
But the issue of how the contentious seabed - which contains a plethora of rich oil fields - will be delineated between the countries will still need further negotiation.
Before heading to Aktau, Iranian President Hassan Rouhani said under the convention, all legal issues of the sea should be implemented through the consensus of the five littoral states, stressing that the agreement did not include dividing the waters.
The Caspian Sea is the largest enclosed water body on the Earth by area, with shared borders between Iran, Azerbaijan, Russia, Kazakhstan and Turkmenistan. "This will contribute to the development of our cooperation in the Caspian region", Putin stressed.
There are some 50 billion barrels of oil and almost 9 trillion cubic meters of gas in proven or probable reserves in the Caspian seabed.
The Caspian Sea Convention determines the territorial rights of littoral states as well as other matters related to the sea.
People exercise on a beach on the Caspian Sea in Baku, Azerbaijan, in 2015. When the Soviet Union split up, suddenly there were five littoral states.
However, there was little detail about provisions on splitting the seabed.
This weekend, watch for the Perseid Meteor Shower
When to watch the Perseids Meteor Shower in India? It's best seen in dark skies after 10pm, with more meteors closer to dawn. What exactly is a meteor shower? As long as it's a clear night, the meteors will be visible to the naked eye.
At stake are the Caspian's vast oil and gas reserves.
It's estimated there are 50 billion barrels of oil and almost 8.4 trillion cubic metres of natural gas beneath its seabed.
Nevertheless, analysts caution that Turkmenistan's long-held plan to send gas through a trans-Caspian pipeline to markets in Europe via Azerbaijan is not necessarily closer to becoming reality.
Nevertheless, Iran and Russian Federation could still challenge the pipeline on ecological grounds.
According to the Russian president, the necessary regulatory base for the settlement of the legal status of the Caspian Sea will be provided by six agreements in the spheres of economy, transport and security, which were also signed on Sunday.
The Caspian Sea has a number of different species of sturgeon, the fish that yields the highly prized delicacy caviar. On occasion, warships have been deployed to scare off contractors hired by rival countries.
It remained unclear whether the convention adopted on Sunday would definitely clear a way for the pipeline.