TOKYO, June 25 (Xinhua) -- A sea-based protest was held in Okinawa Prefecture on Monday by residents demonstrating again the central government's plans to reclaim land from the sea to build a replacement facility for the U.S. Marine Corps Air Station Futenma.

Around 70 canoes and a number of other small vessels were used by the demonstrators who faced off with patrol boats from the Japan Coast Guard, according to local media reports.

The demonstration took place in the pristine and environmentally delicate Henoko coastal area of Nago where the new U.S. base is expected to be relocated to.

Currently the base is located in the densely populated Ginowan district.

Calls form local residents and officials have become more vociferous of late, with Okinawans wanting the base moved off the island or out of Japan altogether.

The protestors were holding placards saying "Don't build a U.S. base here!" and "This area and its beautiful sea must be protected."

The central government began constricting seawall in April last year, triggering a number of protests from Okinawans who wish to see their base-hosting burdens lifted and the local environment protected.

Okinawa hosts the bulk of U.S. military facilities in Japan, yet the tiny sub-tropical island accounts for just a small fraction of Japan's total landmass.