Thousands of people gathered Sunday outside the Diet to protest the plan to move U.S. Marine Corps Air Station Futenma to the Henoko district in Okinawa from the city of Ginowan.

Various speakers addressed what they described as the harmful presence of U.S. forces in Okinawa, including excessive force to clamp down on protesters and environmental damage, and the government's refusal to address these concerns.

The speakers included Australian-born Catherine Jane Fisher who, addressing the crowd through a translator, delivered an "open message to Prime Minister (Shinzo) Abe."

Fisher argued that if terrorism is "violence against civilians for political goals" then "we have terrorists in Okinawa," referring to what she said was excessive use of force by the police against local residents taking part in anti-base protests.

Fisher is known for her long history of political activism and advocacy for sexual assault victims after her traumatic experience of being raped by a U.S. serviceman in Japan in 2002.

She also said construction of the replacement base for Futenma will cause environmental damage in the Henoko area, including to the dugong population and coral reef. "Don't rape us," Fisher said. "Don't rape the sea."

Meri Joyce of the Tokyo-based nongovernmental organization Peace Boat said her group has used "every democratic process and none of it is having an impact."

The protesters then formed a ring around the Diet, temporarily blocking the street before police moved them.