The $15 billion Nord Stream pipeline, which was approved by Denmark last month, also needs the OK from the governments of Finland, Russia and Germany. Once completed it would carry 55 billion cubic meters of gas each year from the Russian port of Vyborg to the German port of Greifswald.

Environment Minister Andreas Carlgren _ who last year expressed concerns about the project's impact on ecosystems in the Baltic Sea _ said Swedish authorities were satisfied with additional information supplied by pipeline builder Nord Stream AG.

Carlgren told reporters in Stockholm that saying no to the project would "contravene international law."

Among the chief environmental concerns were that construction would disrupt fish stocks and sea birds and release toxins from munitions and chemical weapons sprinkled across the sea bed since the world wars of the 20th century.

The project has also met objections in Poland and other countries that currently get transit fees from Russian gas crossing their territory in land-based pipelines. In 2007, Estonia refused to allow the pipeline to run through its waters.

Under current plans the pipeline's route goes through the territorial waters of Russia, Germany and Denmark and through international waters that are part of the exclusive economic zones of Finland and Sweden.

A 300-mile (480-kilometer) stretch of the 750-mile (1,200-kilometer) pipeline would pass through Sweden's economic zone. Construction is planned to start next year.

Russia's Gazprom holds a 51 percent stake in the project, while German energy companies E.ON Ruhrgas AG and Wintershall AG each hold 20 percent. Dutch company Nederlandse Gasunie NV holds the remaining 9 percent.

Nord Stream said the Swedish approval brought it "another step closer to its planned start of construction in Spring 2010. Nord Stream is aiming to obtain all required permits by the end of 2009."

Finnish Prime Minister Matti Vanhanen last month said Finland would likely issue permission for the pipeline following an environmental check.

His remarks came after Russian Prime Minister Vladimir Putin said Russia will further delay the introduction of a higher export duty on raw timber that has worried Finland.