Prime Minister Shinzo Abe said Tuesday he plans to visit Russia early next year to continue negotiations on the long-running territorial dispute over the four Japan-claimed islands off Hokkaido.

"You can't conclude a peace treaty only with one or two (summit) meetings. It's not such an easy task," Abe said in a speech to business leaders at a Tokyo hotel. "I'd like to accelerate moves toward improvement of the relationship" with Russia.

Abe also defended the outcome of his high-profile meetings with President Vladimir Putin last week.