Russia and the other four states that border the oil-rich Caspian Sea began three days of talks in Moscow on Tuesday on their long-standing dispute over how to divide it up. \"There are still differences on a number of key problems regarding the status of the Caspian,\" Russian Foreign Minister Igor Ivanov said at the opening of the 10th meeting of a working group attended by deputy foreign ministers. Ivanov proposed holding at the end of this year or early next year a meeting of foreign ministers of the Caspian states to \"stimulate the process of negotiation\" on the sea\'s status. Talks on dividing the Caspian have proceeded slowly since the Soviet Union\'s break-up turned the four northern countries - Azerbaijan, Kazakhstan, Russia and Turkmenistan - into separate entities in 1991. Agreement is seen as essential to attracting Western investment in the Caspian, whose oil reserves represent the world\'s largest oil discovery in at least a decade. Azerbaijan, Kazakhstan and Russia agreed in May on how to divide the northern and central parts of the resource-rich sea among themselves, a move strongly criticized by their southern neighbours Iran and Turkmenistan. The three states calculated their shares in proportion to the length of the five Caspian countries\' coastlines, giving Azerbaijan 18 percent, Russia 19 percent and Kazakhstan 27 percent. Iran and Tukmenistan have long been opposed to the median-line division of the sea, instead arguing that each country get an equal 20 percent share. Iran seems to have shifted its position on the issue recently, saying it was not entirely opposed to the median-line division. (AFP)