Russia, Kazakhstan and Azerbaijan have bilateral agreements based on middle lines. Because of their use by the three nations, the middle lines seem to be the most likely method to delimit the territory in future agreements. However, Iran insists on a single multilateral agreement between the five nations (with a goal of one-fifth). Azerbaijan disagrees with Iran over some offshore oil deposits. Occasionally, Iranian patrol boats fired on ships sent by Azerbaijan to explore the disputed area. Similar tensions exist between Azerbaijan and Turkmenistan (the latter claims that the former pumped more oil than had been agreed by a field recognized as divided by both sides). The basis of all differences of opinion is therefore who has access to what. This is important because… The five coastal states reached consensus on the legally binding management of the Caspian Sea through special working groups of an agreement on the legal status of the Caspian Sea.  On the eve of a Caspian summit, the 51st Special Working Group was held in Astana in May 2018 and reached consensus on several agreements: transport cooperation agreements; Trade and economic cooperation; Preventing incidents at sea The fight against terrorism; The fight against organised crime; And cooperation in the area of border security.  That is why differences on how to share some of its huge oil and gas deposits were numerous – and fierce. Warships have sometimes been used to discourage entrepreneurs hired by rival countries.
This is a blessing for both Russia and Iran, which have long been concerned about a U.S. or NATO military presence that is increasing Western influence, particularly over Azerbaijan. However, the agreement does not prevent the shipment of military cargoes through the Caspian Sea, given that both Azerbaijan and Kazakhstan have played logistical supply missions for US and NATO troops in Afghanistan. However, many issues remain unresolved. For example, the delimitation of the seabed itself, which is home to most energy resources, has not yet been identified, meaning that Caspian countries must negotiate bilateral agreements. Differences of opinion on their legal status have also prevented the construction of a gas pipeline by the Caspian Sea between Turkmenistan and Azerbaijan. This would have allowed Turkmen gases to bypass Russia on the way to Europe. Sunday`s agreement helps resolve the dispute. It is significant that Kazakhstan`s president, Nursultan Nazarbayev, said on Sunday that the latest agreement mimicked setting national fishing quotas.