* Authorities believe they have located Nazi train

* Government warns "foragers" they risk hurting themselves

* Says train may contain "dangerous materials" from WWII

By Alexandra Hamilton

WARSAW, Aug 27 (Reuters) - Poland appealed to World War Two buffs and rail enthusiasts on Thursday to stop searching for a Nazi German train believed to have lain undiscovered for 70 years in the southwest of the country and rumoured to carry valuable treasures.

Authorities say they believe they have located the train in the county of Walbrzych, tipped off by a German and a Pole who said through lawyers last week that they had found it and expected 10 percent of the value of the findings as a reward.

The culture ministry said "foragers" had since become active in the area and urged them to stop, saying they risked harming themselves.

"I'm certain the train exists, but it might contain dangerous materials from World War Two," said Piotr Zuchowski, the head of national heritage at the ministry.

"This is an appeal for any further investigations to be put on hold until we have finished the necessary official procedures relating to securing the site."

Local news reports say the train, believed to be military, went missing in 1945, packed with loot from the-then eastern German city of Breslau, now called Wroclaw and part of Poland, as Soviet Red Army forces closed in at the end of World War Two.

The reports said the train was carrying guns, gems and other treasures and, according to local folklore, entered a tunnel in the mountainous Lower Silesian region and never emerged. The tunnel was later closed and its location long forgotten. (Editing by Matt Robinson/Mark Heinrich)

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