Japan's nuclear watchdog says the crippled Fukushima Daiichi nuclear plant is facing an "emergency" that the operator is struggling to contain.
Shinji Kinjo, head of the Nuclear Regulatory Authority task force, told Reuters news agency on August 5 that highly radioactive water has breached an underground barrier and is rising quickly toward the surface.
This means the amount of contaminated water leaking into the Pacific Ocean could accelerate dramatically.
Tepco, the operator of the plant devastated by a earthquake and tsunami in 2011, admitted last month that radioactive groundwater had breached an underground barrier and been leaking into the sea.
But it said it was taking steps to prevent it.
However, Kinjo, said the countermeasures were only a temporary solution, adding Tepco's "sense of crisis is weak."
Based on reporting by Reuters and BBC