NHK has learned that a new reclamation project began as part of a plan to relocate a US military base within Japan's southwestern prefecture of Okinawa.

The central government wants to relocate the US Marine Corps Futenma air station to the Henoko district in Nago City. The base is currently located in the densely populated city of Ginowan.

The Okinawa prefectural government is opposing the relocation plan. It refused to approve the central government's plan to reinforce the soft seabed in Oura Bay off Henoko.

But a court decision was finalized that allowed the central government to override the prefecture's objections and implement the reinforcement plan. Work began in January.

The central government launched a landfill project as part of the reinforcement work on Wednesday. The project is underway in an area that is adjacent to the soft seabed and surrounded by five seawalls.

A video filmed by an NHK helicopter shortly after 10:30 a.m. shows trucks dropping soil into the area.

Sources say this is the first time soil has been placed as part of the reinforcement work. They say seawalls and an offshore work yard have been built for the reinforcement plan.

The central government began accepting bids this month to decide a contractor that will be tasked with driving reinforcement piles into the soft seabed.

It is expected to take about 12 years to complete all construction projects and other procedures necessary for the base relocation.