The FSB seized a computer hard disk containing the map during a search of the environmental centre in the city Ulan Ude in far-eastern Buryatia region, centre spokesperson Sergei Chapkhayev told AFP.

The Ulan Ude centre is part of the Siberian University of Technology and specialises in environmental and geological research.

Chapkhayev said the map was of part of the coast of Lake Baikal, the deepest fresh water lake in the world.

He said the FSB was investigating the "disclosure of a state secret" and had interviewed him as a "witness" in the investigation but no charges have yet been pressed.

During the 1970s Soviet scientists developed finely detailed maps for military purposes of the entire territory of the former Soviet Union, a number of which were classified secret.

"With the development of GPS navigation systems and satellite photos which are available on the Internet, this doesn't make any sense," said Chapkhayev. "This legacy of the Cold War is stopping environmentalists from doing their work".

There have been a number of confrontations between the Russian security service and environmentalists, who have been kept under close scrutiny.

In 1996, Alexander Nikitin, a former Russian navy captain, was arrested for having provided information about accidents involving Russian nuclear submarines to a Norwegian environmental group, Bellona. After a four year legal battle he was finally cleared of the charges.

Later military journalist Grigory Pasko was arrested on treason charges for intending to provide information to the Japanese media about radioactive waste from the Russian navy. He was convicted in 2001 to four years prison but released in January 2003.

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