Three workers at the Fukushima Daiichi nuclear power plant have been exposed to high levels of radiation after reportedly stepping into contaminated water as they battled to make the stricken No 3 reactor safe.
Two of the workers were taken to a special radiation unit at a hospital in Chiba city, east of Tokyo, Japan's nuclear safety agency said.
The workers, who are all in their 20s and 30s, were exposed to between 170 millisieverts (mSv) and 180 mSv of radiation.
This is above the usual legal limit of 100 mSv per year for nuclear power workers in Japan, but below a new limit of 250 mSv, introduced last week to enable them to spend more time inside the crippled facility.
The men were affected while laying cable in the turbine building of the No 3 reactor, said Fumio Matsuda, an agency spokesman.
Japan Disaster toll tops 9,800
Japan's police agency says more than 9,800 people are dead after an earthquake and tsunami. Another 17,500 are missing.
Those tallies may overlap, but a police spokesperson from one of the hardest-hit prefectures, Miyagi, estimates that the deaths will top 15,000 in that region alone.
Police in other devastated areas declined to estimate eventual tolls, but said the confirmed deaths in their areas already number about 4,100.
The National Police Agency said the overall number of bodies collected so far stood at 9,811, while 17,541 have been listed as missing.