Officials are particularly concerned about Japanese companies distributing calendars, leaflets, and maps that show the disputed southern Kurile islands as belonging to Japan.
Russia seized the islands, known as the Northern Territories in Japan, at the end of World War II. The dispute has kept Russia and Japan from signing a peace treaty.
Japan renounced its claims to southern Sakhalin after the war, but has not officially recognized Russian sovereignty.
World War II: 60 Years On
A microsite devoted to RFE/RL's coverage of the 60th anniversary of the end of World War II in May 2005.