Russian President Vladimir Putin said Thursday he wants to conclude a postwar peace treaty with Japan but that the process is challenging due to Tokyo's military cooperation with Washington.

Speaking in a meeting with news agencies, Putin said Japan needs to take heed of Russia's security concerns, although he acknowledged it has the right to defend itself.

Putin made the remarks ahead of his planned summit with Prime Minister Shinzo Abe on the sidelines of a Group of 20 summit in Osaka later this month, dampening expectations for a breakthrough in ongoing talks on a treaty and a long-standing territorial dispute over the sovereignty of four Russian-held islands off the coast of Hokkaido.