Highly radioactive water has been found for the first time outside one of the reactor buildings at the quake-hit Fukushima nuclear plant. Officials said, the leak in a tunnel linked to reactor No. 2 has raised fears of radioactive liquid seeping into the environment. They said the radiation scare inside the reactor was caused by a partial meltdown of fuel rods. Up until now, pools of water with extremely high levels of radiation have only been detected within the reactor buildings themselves. The discovery comes as Japan's Chief Secretary said that the priority at the plant was to ensure that contaminated water did not leak into the soil or the sea. The Chief Secretary was speaking at a news conference a day after TEPCO said radiation levels at reactor No.2 were 10 million times higher than normal before correcting that figure to 100,000. Earlier, Japan government strongly criticised the plant's operator, TEPCO, over mistaken radiation readings.