Russia on Saturday slammed the United States for meddling in Russia-Japan relations by exerting pressure on Tokyo.   "Under the consistent pressure from Washington, Tokyo has narrowed our engagement channel in bilateral directions...Japanese officials have been discouraged from visiting Russia," Foreign Ministry spokeswoman Maria Zakharova told Russia's RT television.   She said that relations between Russia and Japan are not developing as well as Moscow has expected, adding that it was mostly a result of Japan's sanctions against Russia and the steps taken by the U.S. and the European Union in response to the Ukraine crisis.   Russian Foreign Minister Sergey Lavrov is currently visiting Tokyo to mend ties that have been strained due to the two nations' long-held territorial disputes.   The two sides on Friday agreed to schedule a date for Japanese Prime Minister Shinzo Abe to meet Russian President Vladimir Putin in Russia. Meetings between senior officials of the two sides are also under discussion so as to talk about the territorial disputes. Source: Xinhua