Poland's defense minister says army experts have found no dangerous objects or substances on the surface of the site of an alleged World War II Nazi train.

A recent claim by two explorers that they have located a Nazi train with armaments and precious substances hidden in a secret tunnel has provoked a gold rush in the region of Walbrzych, in southwestern Poland. Local authorities asked the military to check the terrain for safety.

Sappers in full gear with earth-penetrating radars and chemicals experts checked the ground this week, going one meter deep.

Minister Tomasz Siemoniak said Friday they have found no dangerous materials. But they have not reported any trace of the train, either.

It was not clear if deeper checks will be undertaken.