The leaders of the five Caspian Sea states, including Russia, pledged at a summit in Tehran in October to overcome differences on dividing the sea and its resources but failed to agree on boundaries or a final share.
Iran wants all resources shared equally among the five states, even though its coast accounts for less than 14 percent.
“Based on this principle (principle of fairness) … our share would be 20 percent,” Iranian Foreign Ministry spokesman Mohammad Ali Hosseini told a news conference.
“In order to reach this share, we have always made an effort and we are not going to retreat from our share,” he said.
The other littoral states are Kazakhstan, Azerbaijan and Turkmenistan.
At stake are estimated oil reserves of as much as 49 billion barrels — equal to about half that of an OPEC member such as Kuwait — and reservoirs with 230 trillion cubic feet of gas. The Caspian is also the world’s main source of caviar.
The October summit did not agree on a new pact to replace agreements on the sea’s status dating from the era of the Soviet Union. It said setting up a legal regime for it was “the most important duty” but did not give a timetable for achieving this.
Azerbaijan and Kazakhstan in particular have been quick to extract hydrocarbons, even without a final deal. They have signed bilateral accords with Russia. Iran opposes such deals.
Without a comprehensive pact on sharing resources or clear demarcation of boundaries, tensions can grow. Ownership of several big oilfields is hotly contested.
Russia has argued for dividing the seabed between the five states but keeping the waters in common use. Some experts say this is so it has more room to manoeuvre its Caspian navy of around 100 ships, far larger than any other coastal state. (Reporting by Hossein Jaseb, writing by Fredrik Dahl; Editing by Peter Blackburn)
