Tokyo Electric Power Co. has released dramatic images taken by an underwater camera showing major damage at a spent fuel storage pool at the Fukushima Daiichi nuclear plant.

Photos show a 35-tonne crane, set to straddle over the pool, which may have dropped due to a hydrogen explosion three days after the tsunami and earthquake on March 11 last year, TEPCO said when it released the images on Friday.

Twisted fragments from iron frames of the No.3 reactor building were also seen in the 11.8-meter-(39-foot) deep pool.

It was the second time TEPCO released underwater images from inside the reactor building.

There are six reactors at the plant and the No. 3 unit is among three which have suffered meltdowns after the quake-tsunami disaster.