(Reuters) - Japanese authorities advised against allowing infants to drink tap water in Tokyo due to raised radiation levels and the United States became the first nation to block some food imports from Japan.
The crisis at the tsunami-smashed nuclear power plant, 250 km (150 miles) north of the Japanese capital, appeared far from over with workers attempting to gain control ordered to leave the site after black smoke began rising from one of its six reactors.
The plant was crippled by a 9.0 magnitude earthquake and tsunami on March 11. Some 23,000 people have been left dead or missing.
Tokyo authorities said water at a purification plant for the capital of 13 million people had 210 becquerels of radioactive iodine -- more than twice the safety level for infants.
"This is without doubt, an effect of the Fukushima Daiichi plant," a Tokyo metropolitan government official said, referring to the nuclear power station.
Tokyo governor Shintaro Ishihara, however, said the radiation level posed no immediate health risk and water could still be used.
"But for infants under age one, I would like them to refrain from using tap water to dilute baby formula," he said.
International concerns about food safety are growing, with the United States the latest to impose controls. The U.S. Food and Drug Administration said it was stopping imports of milk, vegetable and fruit from four prefectures in the vicinity of the crippled nuclear plant.
South Korea may be next to ban Japanese food after the world's worst atomic crisis since Chernobyl in 1986. France this week asked the European Commission to look into harmonizing controls on radioactivity in imports from Japan.
Food made up just 0.6 percent of Japan's total exports last year.
Authorities said above-safety radiation levels had been discovered in 11 types of vegetables from the area, in addition to milk and water.
Officials still insisted, however, that there was no major danger to humans and urged the world not to over react.
"We will explain to countries the facts and we hope they will take logical measures based on them," Japan's chief cabinet secretary Yukio Edano, who has been the government's public face during the disaster, told a news conference.
Japan has already halted shipment of some food from the area and told people there to stop eating leafy vegetables. Asian neighbors are inspecting imports for contamination, and Taiwan advised boats to stop fishing in Japanese waters.
At the Fukushima plant, engineers are battling to cool reactors to contain further contamination and avert a meltdown.