Berlin  - Thousands of anti-nuclear demonstrators were trying Saturday to obstruct a tightly guarded convoy of spent nuclear fuel on its way to a German waste dump.

Near the warehouse in Gorleben in the northern German countryside where many tons of radioactive waste are stored, more than 6,000 militants thronged roads just before a protest rally.

In the south of Germany, other protesters invaded railway tracks expected to be used by the freight train convoy when it arrived from a French waste-reprocessing plant at La Hague on the Atlantic coast.

Two men and a woman chained themselves to the rail track at the small border town of Berg. A police spokesman said it would be difficult to cut them free.

Protesters said the train was waiting at Lauterbourg on the French side of the border.

The anti-nuclear movement seeks the immediate closure of all nuclear power stations and believes that waste transport and storage is unsafe. Police said they expected picketers to try forcibly to block the convoy route through Germany.

Germany is studying whether to use an old saltmine near the warehouse in Gorleben as long-term storage for the waste.

The convoy Saturday, carrying 17 tons of waste encapsulated in 100 tons of glass, was the 11th over the years to carry spent waste to the small town.

More than 10,000 German police were detailed to protect the convoy. (dpa)