Tens of thousands of protesters gathered on August 11thSaturday in Okinawa vowing to stop the planned relocation of a US military base on the southern Japanese island.

Opponents of the relocation said the plan to move US Marine Corps Air Station Futenma from a crowded neighbourhood to a less-populated coastal site would not only be an environmental debacle but also ignores local wishes to have the base moved from the island entirely.

About 70,000 people gathered at a park in the state capital of Naha under pouring rain in advance of an approaching typhoon and observed a moment of silence for Okinawa's governor, Takeshi Onaga, who died Thursday of cancer.

Onaga, elected in 2014, had spearheaded opposition to the relocation and criticised the central government for ignoring the voices of Okinawans. He had filed lawsuits against the central government and said he planned to revoke a landfill permit issued by his predecessor that is needed for construction of the new base.

'Determination and passion'

Deputy Governor Kiichiro Jahana, representing Onaga at Saturday's rally, said he will follow through with the revocation process as instructed by the governor and succeed his "strong determination and passion".

Okinawans are trying to block the central government plan to start dumping soil into Henoko Bay within days to make a landfill for the new site of the Futenma base. Environmental groups say construction risks corals and endangered dugongs.

Saturday's protesters held up signs saying "Henoko new base, NO!" and "Okinawans will not give up" as they chanted slogans. They also adopted a resolution demanding the central government to immediately scrap the relocation plan.

25,000 US troops

The central government says the current plan is the only solution, but many Okinawans want the base entirely moved outside of Okinawa. About half of the 50,000 American troops in Japan are stationed on Okinawa.

Onaga had said Tokyo's post-war defence stance under the Japan-US security alliance was built on Okinawa's sacrifice.

The dispute over the Futenma relocation reflects centuries-old tensions between Okinawa and the Japanese mainland, which annexed the islands, formerly the independent kingdom of the Ryukus, in 1878. Okinawa was Japan's only home battleground in the final days of World War II, and the island remained under US rule for 20 years longer than the rest of Japan.

Okinawa is still forced to sacrifice for the interest of the mainland, Onaga's son Takeharu, an Okinawa assemblyman, said at Saturday's rally.

"The [relocation issue] is pushed to Okinawa because nobody on the mainland wants it," he said, urging the rest of the country to also think about the issue. "Let us keep fighting so we can achieve my father's unfinished goal and give him good news."