Three months after the Okinawa Defense Bureau started seawall construction off the coast of Nago in Okinawa’s Henoko district, work to build a replacement facility for a U.S. military base in Ginowan is moving forward — and along with it, renewed legal and political resistance to the controversial plan.

On Tuesday, an Okinawa Prefectural Assembly committee passed a resolution calling for legal action to halt the crushing of rocks and offshore reefs related to the landfill project, citing damage to fishing grounds. If the full assembly, which is controlled by opponents of the Henoko plan, passes the resolution on Friday, formal legal proceedings against Tokyo could begin next week.

“The granting of fishing rights is considered a local government matter and it’s the prefecture that determines how to interpret those local government matters,” Kiichiro Jahana, the head of the Executive Office of the Governor, told the assembly Tuesday in justifying the decision for legal action, according to local reports.

To support the action, Henoko opponents also said Tuesday they would stage a rally on August 12 that they hoped would draw 30,000 people, including Okinawa Gov. Takeshi Onaga, who has strongly opposed the Henoko relocation of U.S. Marine Corps Air Station Futenma.

“The central government is forcing construction to proceed, but we want to ensure that the Okinawan people will not be silenced and that their voices will be heard in and out of Japan,” Suzuyo Takazato, one of the organizers, told local media Tuesday.

From Aug. 16 to 24, a delegation of Okinawan activists opposing the construction of the base will take their message to California, where they will participate in gatherings with local politicians sponsored by the Asia Pacific American Labor Alliance.

The new legal effort by politicians and activists in Okinawa to stop Henoko’s construction comes as no surprise. Onaga vowed to press forward with other legal measures after the Supreme Court ruled in December that the governor had no legal standing to cancel in 2015 a landfill permit for the project that had been issued by his predecessor.

In February 2014, the central government reportedly told Okinawa it would agree to close Futenma within five years. But progress was contingent upon Okinawa’s cooperation in agreeing to the Henoko relocation.

In April, seawall construction began, involving in its preliminary stage crushing rocks and coral. Once completed, the next stage is for earth and sand to be poured into the area to create an artificial island that will include two runways. Depending on what the court says, that work could begin as early as March 2018.

Information from Kyodo added.