The government will attempt to accelerate the construction of seawalls at the planned site of a controversial U.S. air base in Okinawa by delivering rocks by sea Tuesday, according to government sources.

The decision will likely draw the further ire of the prefectural government, residents and environmental campaigners opposed to the relocation of the Futenma base from the city of Ginowan to the coastal area near Henoko.

Ships delivering the rocks will dock alongside existing seawalls that are serving as a pier on the northern side of the area to be filled, the sources said Monday.