(Photo: REUTERS)

Bloomberg news on Thursday also reported that the United States and Ukraine's allies were considering "an outright ban on most exports to Russia".

That report said officials from G7 nations were discussing the idea before a summit meeting in Japan next month.

Asked about the Bloomberg report, Japan's Chief Cabinet Secretary Hirokazu Matsuno said the government was aware of it but refrained from commenting on exchanges among G7 countries and like-minded nations about possible further sanctions against Russia.

He told a press briefing that what is important for ending the conflict as soon as possible is that G7 remains united for severe sanctions against Russia and strong support for Ukraine.