Okinawa on Friday marked 72 years since the end of a fierce World War II ground battle that killed a quarter of its civilian population, as resentment continues to run deep over the heavy concentration of U.S. military bases there.

Touching on a U.S. Osprey that ditched off the main island in December and other accidents, Okinawa Gov. Takeshi Onaga said at a memorial service for the war dead the same day that residents' needs weren't being addressed.

"We see moves running counter to a reduction of the burden," Onaga said.