(Adds Japan's reaction, context)
MOSCOW Aug 22 (Reuters) - Russia on Friday banned several Japanese citizens from entering the country, expanding retaliatory measures against countries which have imposed sanctions over the crisis in Ukraine.
Russia's foreign ministry said in a statement that the ban was a response to visa restrictions that Japan had imposed on a number of Russian citizens. Neither the Russian nor Japanese foreign ministries said who was on the list.
"Such counter-measures will have a negative impact on Japan-Russian relations and it is extremely regrettable," the Japanese foreign ministry said in a statement.
The United States and the European Union have imposed sanctions on Moscow for the annexation of Crimea and for what the West says is Moscow's support of separatists fighting the forces of Kiev's pro-Western government in eastern Ukraine.
On Friday, the crisis escalated further as Russia sent a convoy of aid trucks across the border without either Kiev's consent or an escort of international observers in what the EU said was a clear violation of Ukraine's border.
Japan's sanctions on Russia are lighter than those of its close ally, the United States, and the European Union as it tries to prevent significant damage to relations with Moscow.
Japan is hoping to forge closer energy and economic ties with oil and gas-rich Russia following decades of strained relations between the two countries since the end of World War Two over disputed islands in the Pacific.
Russia seized the islands - known as the Southern Kuriles in Russia and the Northern Territories in Japan - near the end of World War Two and the dispute has prevented the neighbours from signing a formal peace treaty.
This month, Japan "strongly protested" against exercises on the islands in which Russia said more than 1,000 soldiers, five attack helicopters and 100 other pieces of military hardware were involved.
Russia plans to at least double oil and gas flows to Asia in the next 20 years, while Japan has resorted to huge fuel imports to replace lost nuclear energy, after reactors were shut down because of the 2011 Fukushima disaster. (Reporting by Katya Golubkova in Moscow and Stanley White in Tokyo,; Writing by Christian Lowe and Dmitry Zhdannikov)