Ukraine accused Russia on Tuesday of effectively cutting the Ukrainian port of Pivdennyi out of a deal allowing safe Black Sea grain exports as Russia complained that it had been unable to export ammonia via a pipeline to Pivdennyi under the pact. The Black Sea deal - brokered last July by the United Nations and Turkey and extended last week for two months - covers the wartime export of food and fertiliser from the Ukrainian ports of Odesa, Chornomorsk and Pivdennyi.