Japanese authorities are investigating the discovery of a suspected unexploded World War II-era bomb at the Fukushima nuclear plant, which went into meltdown in 2011.

The object was discovered by workers at the plant, Tokyo Electric Power Company (TEPCO) announced on Thursday.

Read more

According to Japanese news agency Jiji Press, the suspected device is 85cm (33in) in length and about 15cm (6in) wide.

It was discovered by a subcontractor working in an area nearly half a kilometer from the hub of the plant. The area was designated as a difficult-to-return zone in the aftermath of the disaster at the power plant.

Police are investigating the nature of the device and exploring disposal options if it is confirmed to contain explosives, Mainichi reports.

On March 11, 2011 a major earthquake triggered a tsunami which struck the six-reactor plant, causing serious damage. Units 1-3 went into meltdown in what was the worst nuclear disaster since Chernobyl in 1986.

The area surrounding the Fukushima plant was evacuated during the crisis, and tens of thousands of people remain displaced.

AFP reports that a Japanese military airport was in the area close to the Fukushima plant during World War II, and was targeted by US bombers.