UKRAINE said an agreement to resume grain exports blocked by Russia appeared close as Turkey hosted four-way talks, raising hopes of an end to a standoff that has exposed millions to the risk of starvation. Several Ukrainian cities meanwhile reported heavy Russian shelling. ECONOMY/DIPLOMACY * Delegations from Ukraine, Russia and Turkey met U.N. officials in Istanbul to discuss resuming exports of Ukraine grain from the Black Sea port of Odesa. Kyiv believed a deal was "two steps away", Foreign Minister Dmytro Kuleba was quoted as saying, though other participants seemed less optimistic and Turkey's defence ministry gave no details of…