Two workers at Japan's damaged Fukushima Daiichi nuclear power plant have been taken to hospital after being exposed to high levels of radiation.
The injured workers were contaminated with up to 180 millisieverts of radiation, close to the recommended limit, after working in water 30 centimetres deep while laying a power cable.
The men suffered radiation burns on their feet after water seeped into their boots. Another man also suffered burns, but he did not require hospitalisation.
Engineers are trying to stabilise the facility nearly two weeks after an earthquake and tsunami battered the complex and devastated northeast Japan.
Meanwhile, many shops in Tokyo have run out of bottled water after radiation from a damaged nuclear plant made tap water unsafe for babies.
Tokyo's 13 million people have been told not to give infants tap water because of contamination twice the safety level.
The government urged residents not to panic and hoard bottled water but many shops quickly sold out.
"If this is long term, I think we have a lot to worry about," said Riku Kato, father of a one-year-old baby.
Radiation above safety levels has also been found in milk and vegetables from the area around Fukushima, 250km north of Tokyo, and in Saitama prefecture next to the capital, according to Kyodo news agency.
Singapore and Australia joined the United States and Hong Kong in restricting food and milk imports from the zone, while Canada became the latest among many nations to tighten screening as a result of the world's worst atomic crisis since Chernobyl.
Radiation particles have been found as far away as Iceland, although Japan insists levels are not dangerous to adults.
The contamination scare is adding to Japan's most testing moment since World War II after the catastrophe of March 11th.
The estimated $300 billion damage makes it the world's costliest natural disaster, dwarfing Japan's 1995 Kobe quake and Hurricane Katrina that swept through New Orleans in 2005.
Some 25,600 people are dead or missing from the 9.0 magnitude earthquake and ensuing tsunami waves that swept away whole towns on the Pacific coast.
In Japan's devastated north, more than a quarter of a million people are in shelters. Some elderly refugees, among an ageing population, have died from cold and lack of medicines.
Exhausted and traumatised rescuers are still sifting through the mud and wreckage where towns and villages once stood.
The official death toll from the disaster has risen to 9,523, but is bound to rise as 16,094 people are still missing. Aftershocks are still coming, and an earthquake with a preliminary magnitude of 6.1 hit northern Japan this morning.
Agencies