"I don’t even want to comment on the protest allegedly lodged by Japan… With the plane’s nationality still unknown, what kind of a protest can we talk about?” a source at the Russian embassy in Tokyo told RIA Novosti news agency.
“The Japanese side asked us to clarify the situation and we are checking the facts now,” the source added.
On Tuesday the Japanese Self-Defense Forces said that the unidentified plane entered the country’s airspace off the coast of the northernmost main island of Hokkaido, near a disputed island chain, on Tuesday afternoon.
Sixteen seconds after entering Japanese airspace in the north-south direction, the plane turned east and then proceeded northwards.
