Okinawa Prefecture retracted Friday its approval for landfill work for the relocation of a key U.S. military base, citing illegalities in the procedure, in line with an instruction from late Okinawa Gov. Takeshi Onaga.

The withdrawal of the approval, which was granted by Onaga's predecessor in 2013, is seen as a last-ditch attempt to block the planned transfer of U.S. Marine Corps Air Station Futenma within the prefecture.

Before his death from pancreatic cancer on Aug. 8, Onaga had instructed local officials to launch procedures to retract the decision. The central government has postponed landfill work that was scheduled to begin on Aug. 17 without providing any explanation for the decision. The prefectural government's move is expected to draw voters' attention to the controversial base relocation issue in the run-up to the Sept. 30 contest to pick Onaga's successor as well as a series of local assembly elections earlier in the month.