The Okinawa prefectural government on Thursday lodged an official complaint with the U.S. military after a PET water bottle fell from an MV-22 Osprey aircraft during a training flight near the Futenma air base in Ginowan.
Sankei Shimbun reported that the incident occurred on Tuesday afternoon. The 20-cm-long bottle landed outside the base.
A prefectural government official delivered a letter of protest to the U.S. Marine Corps, urging the U.S. side to make sure such an incident does not happen again.
Sankei quoted Marine Corps spokesman William Truax as saying that the incident occurred due to human error.
The deployment of the Osprey aircraft last summer has been a source of friction between the Okinawan government and the U.S. military.