Japan and Russia are making arrangements for a close aide to Russian President Vladimir Putin to visit Japan in late September, sources said Tuesday.

By arranging the visit by Nikolai Patrushev, secretary of the Security Council of Russia, Tokyo hopes to discuss Putin's possible visit to Japan by the end of this year and push for a possible summit between Prime Minister Shinzo Abe and the president on that occasion.

But the United States may still express caution about a visit by Putin's close aide to one of its allies at a time when Washington and Moscow remain at odds over developments in Ukraine.