The 1945 battle during the final phase of World War II, whose anniversary was observed Tuesday in Okinawa Prefecture, resulted in the deaths of more than 200,000 people, Kyodo reported.
"I have not forgotten that the peace and prosperity of Japan today has been built on the grave sacrifices of those who perished in the war," Aso was quoted by the Japanese news service as saying. "We must never repeat the horror of war."
At a ceremony at the Peace Memorial Park in Okinawa's Itoman town, Gov. Hirokazu Nakaima asked the U.S. and Japanese governments to consolidate and reduce U.S. bases in Okinawa, Kyodo said.
The governor reminded about the danger of unexploded shells still remaining in the battlefields of Okinawa, which was under U.S. occupation until 1972, the news agency said. Aso pledged to make every effort to clear them.
Military-related noise also has been a problem on Okinawa. A 2006 U.S.-Japan agreement called for measures to reduce it and hold training for fighter planes at bases outside the prefecture. However, Kyodo quoted residents as saying the deployment of new F-22A Raptor stealth fighters has only increased the noise problem.