Japan is discussing a ban on oil imports from Russia with the United States and European countries, a government source close to the matter said Monday, as Moscow's attack on populated areas and civilian infrastructure in Ukraine continues.

Prime Minister Fumio Kishida said Japan still has "several more options" for sanctions against Russia, underscoring the need for Japan to act with Western countries in dealing with Russia's aggression against Ukraine. But he refrained from saying whether Japan will join the United States and European nations in banning Russian flights from its airspace.

While the international community has been stepping up pressure on Russia since its invasion on Feb. 24, U.S. Secretary of State Antony Blinken said Sunday that Washington and European allies are now exploring banning imports of Russian oil.