Japan's Defence Minister said on Sunday Japan may have to consider negotiating changes in the agreement that governs the status of US forces in Japan following a dispute over the management of a US helicopter crash in the southern prefecture of Okinawa earlier this month.
"If the Status of Forces Agreement has been used arbitrarily, we have to discuss ways of preventing this from happening," Shigeru Ishiba said on a programme broadcast by public television. "If the discussions make no progress, the issue of revision will arise," he added.
Japan lodged a protest with the US embassy last week after the United States flew CH-53D Sea Stallion helicopters over its territory without having provided a full explanation for an August 13 crash involving the same model of helicopter.
The aircraft crashed into a university in Okinawa, damaging buildings, but causing no injuries. Japanese police were initially kept out of a probe into the crash.
The US embassy on Saturday announced that all CH-53D flights within Japan had been suspended until a safety review is completed.
The Status of Forces Agreement (SOFA) defines the status of the 48,000 US military personnel based in Japan. Its terms are often criticised by Japanese angered by crimes committed by US servicemen, particularly the 1996 rape of a 12-year-old girl by three US military personnel.