Switzerland on Monday suspended plans to replace its ageing nuclear power plants amid fears of a nuclear disaster in Japan, stressing that safety was an aboslute priority.
The Federal Office for Energy said authorities decided to suspend ongoing procedures regarding authorisation requests for the replacement of nuclear power plants "until security standards can be carefully re-examined and, if necessary, adapted."
It added that the Federal Inspectorate for Nuclear Security had been ordered to "analyse the exact causes of the accident in Japan and to draw conclusions on possible stricter new standards."
The energy office said that any authorisation requests to replace the country's five nuclear plants "cannot be evaluated before these clarifications."
"The security and well-being of the population is the absolute priority," said transport and energy minister Doris Leuthard.
In Switzerland, where there is a chance of a 7.0-magnitude earthquake in one in every 100,000 years, all but one nuclear plants are able to withstand quakes of up to that scale, the Swiss news agency ATS reported.
But fears of a catastrophic meltdown at the Fukushima-Daiichi nuclear plant in Japan has revived the debate in Switzerland, where cantons are in the process of holding consultation polls on renewing three of its plants.
An explosion rocked a building housing a nuclear reactor at Japan's quake-damaged Fukushima power plant earlier Monday, the second such blast in two days following Friday's devastating earthquake and tsunami.
The cooling system has also failed at a third reactor there.
Japan's operator TEPCO said Monday a fuel rod meltdown at the plant could not be ruled out after water levels dropped sharply, Jiji Press reported.
Engineers are struggling to cool down three reactors at the Fukushima 1 plant, which has been hit by two explosions.
The unfolding disaster has sparked a debate around the developed world, where nuclear energy has been sold as a clean alternative to coal and fuel.
In Washington, lawmakers have called for a slowdown in nuclear development.
US President Barack Obama is aiming to increase nuclear power as part of a US effort to decrease the nation's dependence on coal and imported oil.
While the White House said Sunday that policy remains in effect, it sounded a note of caution.
"Information is still coming in about the events unfolding in Japan, but the administration is committed to learning from them and ensuring that nuclear energy is produced safely and responsibly here in the US," White House spokesman Clark Stevens told The New York Times.
The Japan crisis has also put German Chancellor Angela Merkel under pressure over her decision to postpone the switch-off of all nuclear reactors by a decade.
Germany decided in 2000 under the SPD and the ecologist Greens to switch off the last of its 17 nuclear power stations by 2020, but Merkel's government in 2010 postponed the exit until the mid-2030s, despite strong public unease.
And Britain's energy minister Chris Huhne said Sunday that lessons needed to be learned from the Japanese nuclear accident.
"We have to learn the lessons from what has gone on in Japan and make sure we take them on board," he said.
In June, British authorities are due to authorise the use of EPR (European Pressurised Reactor) technology by the French Areva and EDF groups and the AP1000 design of the US company Westinghouse in the building of new nuclear reactors.