"Six or seven people were killed but the death toll could get worse," said Florian Schroffenegger of the fire services department of Bolzano, in the Alto Adige region.
He said five of those injured were in a serious condition following the peak-time accident, which took place at 9am local time.
Thomas Widmann, transport adviser to the Bolzano provincial government, told Sky Italia television that the landslide, which derailed the two-carriage train appeared to have been caused by a burst irrigation pipe.
Television images showed the train had slid down a slope and been stopped by a line of trees.
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