"All kinds of energy production have an environmental impact", Sweden's Prime Minister Fredrik Reinfeldt said.

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VILNIUS (AFP) - The nuclear crisis in Japan must not spark a headlong return to fossil fuels, Sweden's Prime Minister Fredrik Reinfeldt said Tuesday in Lithuania, which aims to open an atomic power plant by 2020.

Reinfeldt said lessons from Japan should instead help boost nuclear security worldwide, including in Sweden, which has 10 reactors.

"But it's also very important to say that all kinds of energy production have an environmental impact," he told reporters alongside his Lithuanian counterpart Andrius Kubilius.

Reinfeldt stressed that fossil fuels are a "driving force behind climate change".

"So to say that just to shift over to fossil fuel is a better solution -- I would argue against, because there you will have more of the climate effects," he added, underscoring the need to focus on alternative energy.

Kubilius said Japan's crisis pointed up shortcomings in planned plants near Lithuania’s border -- a Russian-Belarussian project in Belarus and one in Russia's Kaliningrad territory.

"The construction of a nuclear power plant, especially after Japan's events, can be pursued only if all international environmental requirements are implemented absolutely and precisely. We still do not see that, neither from Belarus nor from Kaliningrad," Kubilius said.

Russia's Prime Minister Vladimir Putin on Tuesday ordered an urgent review of Russia's atomic energy sector. But while visiting Belarus, he insisted there was no discussion of shelving projects such as the Belarus plant.

"The protection levels at the Belarus facility will be considerably higher than in Japan, even though Belarus does not lie in this kind of seismic zone," he said.

Lithuania shut down its only nuclear plant -- a Soviet-era facility -- in 2009 under the terms of its European Union entry.

It aims to build a new one by 2020 with Poland and fellow Baltic states Latvia and Estonia, but a top official warned that Japan's crisis could have an impact.

"The psychological influence may have political effects," said Darius Semaska, chief adviser to President Dalia Grybauskaite.

"Probably there will be considerations about additional security measures, and that could increase the price of nuclear energy projects," he added.