Global anxiety rose over radiation from Japan's earthquake damaged nuclear plant even as engineers had some success in the battle to avert disaster from the world's worst atomic crisis since Chernobyl.
The high-stakes drama at the battered Fukushima nuclear power complex is playing out while the Asian nation grapples with the rising death toll from the March 11 double disaster of an earthquake and tsunami. Officials estimate at least 21,000 people are dead or missing.
Technicians working inside an evacuation zone round the stricken plant on Japan's northeast Pacific coast have finally managed to attach power cables to all six reactors and started a water pump at one of them to cool overheating nuclear fuel rods.
"We see a light for getting out of the crisis," an official quoted Prime Minister Naoto Kan as saying, allowing himself some rare optimism in Japan's toughest moment since World War II.
Underlining the dangers, however, smoke rose briefly from two damaged reactors, forcing workers to evacuate for a while.
Away from the plant, mounting evidence of radiation in vegetables, water and milk spread jitters among Japanese and abroad despite officials' assurances levels were not dangerous.
The operator of the stricken plant, Tokyo Electric Power Company, said a small trace of radiation had been found in the Pacific sea waters nearby, but said levels were very low and posed no immediate danger.
"It's a lot more serious than anybody thought in the early days when we thought that this kind of problem can be limited to 20 to 30 kilometres," Peter Cordingley, spokesman for the World Health Organisation's (WHO) regional office, told Reuters.
"It's safe to suppose that some contaminated produce got out of the contamination zone."