The United Nations Secretary General António Guterres in a statement on Monday welcomed signing the landmark convention on the Caspian Sea Legal Regime.
'The Secretary-General welcomes the signing of the Convention on the Legal Status of the Caspian Sea by Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan,' reads the statement appeared on the UN Secretary General's official website.
'This historic document demonstrates the importance of regional cooperation, which is vital for maintaining international peace and security,' it continues.
Presidents of five Caspian Sea littoral states signed on Sunday the convention on the legal status of the Caspian Sea; a landmark instrument that is expected to expand good-neighborly relations among parties including Iran, Azerbaijan, Turkmenistan, Russia and Kazakhstan.
'The Secretary-General believes the Convention should prove invaluable in regulating a wide range of longstanding issues among the Caspian Sea littoral states and is a significant step in the easing of regional tensions,' the statement added.
'The Secretary-General takes this opportunity to congratulate the five signatory countries on this landmark achievement of regional cooperation and multilateralism.'
According to Iranian Foreign Ministry's Center for Public Diplomacy and Media Affairs, around 90 percent of the Caspian Sea legal regime convention has been addressed by the member states.
Only two issues – determining the base lines and delimitation of the remaining seabed and underground resources – need further negotiations, the statement said, expressing hope that these two issues will also become finalized with cooperation of all the member-states.