President Vladimir Putin said on Thursday that Russia had concerns about Japan’s military cooperation with the United States, but respected Tokyo’s right to defend itself anyway it saw fit.

Putin, who was speaking at an economic forum, said Moscow and Tokyo needed to increase trust levels.

The search to find a solution that would allow the two countries to finally and formally sign a World War Two peace treaty was a complex one, he added. But he said that he personally wanted to see it happen as did Japanese Prime Minister Shinzo Abe.