Iran and Turkmenistan have agreed to start work on charting their common border in the resource-rich Caspian Sea, Turkmenistan\'s leading state-run newspaper reported on Friday. The border demarcation \"will allow both states to start active realisation of oil and gas exploration projects in the sea border area\", the Neutralny Turkmenistan daily said. Since the break-up of the Soviet Union, efforts to exploit potentially vast oil and gas reserves beneath the Caspian have been hampered by disputes over the sea borders between Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan. Iran has opposed dividing the sea in proportion to the length of each country\'s coast -- giving it a 13-percent share -- and objected strongly to bilateral accords signed last year to that effect by Azerbaijan, Kazakhstan and Russia. Instead Tehran has argued that the Caspian should be divided equally between the five, which would give it control of some prospective oilfields claimed by Azerbaijan. (AFP)