TOKYO (AP) — Japan's central government has started main reclamation work at a disputed U.S. military base relocation site on the southern island of Okinawa despite fierce local opposition.

Construction workers started dumping a truckload of sediment into the sea at Henoko on Okinawa's east coast Friday.

Opponents of the relocation say the plan to move U.S. Marine Corps Air Station Futenma from a crowded neighborhood to a less populated coastal site at Henoko would not only be an environmental debacle but also ignore local wishes to remove the base.

Dozens of people in rubber boats protested the move.

Okinawans say the presence of so many U.S. troops on the tiny island is already a burden and they want the base off the island entirely.