TOKYO, April 14 -- Tokyo Electric Power Co. (TEPCO) said Monday that about 203 tons of highly radioactive water stored at the crippled Fukushima Daiichi nuclear power plant have been wrongly dumped to a building, local media reported.

Japan's Kyodo News agency cited TEPCO as saying that the contaminated water was accumulating inside the building from Sunday evening.

According to the ill-fated operator of the plant, the misplaced groundwater has an extremely high level of radionuclides. The level of accumulated Cesium has reached 37 million becquerels per liter, while the safety limit stands at 25 becquerels or lower.

While it told reporters that the water is unlikely to have leaked outside the building, as the radiation level of groundwater nearby has not changed.

The Fukushima Daiichi nuclear plant, which was damaged by an earthquake and tsunami in 2011, has faced multiple problems including leaks and power cuts since the disaster. As operator of it, TEPCO has been widely slammed for its extremely poor management.