In a potential setback for Prime Minister Shinzo Abe, Russian President Vladimir Putin is showing no signs of softening his stance on negotiations over concluding a peace treaty with Japan, instead focusing on a proposed joint economic project on disputed islands already rejected by Tokyo.

Speaking at a news conference in Lima on Sunday, Putin said concluding a World War II peace treaty with Japan that has been delayed for decades by the territorial row is "not an easy path."

Putin said he is "ready for dialogue" toward resolving the sovereignty issue over the Russia-held islands northeast of Hokkaido, adding that "there are various options" for settling the row.