Police are checking what appears to be an unexploded bomb found near the crippled Fukushima Daiichi nuclear power plant.
Construction workers found the object on Thursday morning while drilling at a parking lot to expand the site, about 300 meters from the power plant in Fukushima Prefecture.
Police say the object is about 85 centimeters long and 15 centimeters in diameter.
Police were sending the pictures of the object to the Self-Defense Forces to determine whether it could explode, and will consider measures to remove it.
The operator of the power plant, Tokyo Electric Power Company, says an airfield of the now-defunct Imperial Japanese military used to be at the site, and the facility was air raided during World War Two.
TEPCO says an area within 200 meters from the site is cordoned off, but that decommission work for the crippled reactors on the plant premises is underway as usual.