BEIJING (Reuters) - A Siberian tiger released into the wild by Russian President Vladimir Putin is the main suspect in a series of goat deaths in China's northeast, state media reported Chinese local authorities as saying on Tuesday.

Siberian tiger experts have pegged Ustin, one of three tigers freed by Putin, as the killer of two goats, the official Xinhua news agency said.

Three goats are still missing.

According to a Xinhua witness, the dead goats' skulls had been crushed with puncture holes "the size of a human finger clearly visible".

Ustin crossed into China in October with another of Putin's tigers, both of which carry tracking devices, Xinhua said, adding a warning from a wildlife protection expert not to throw food at the tiger if spotted.

(Reporting by Paul Carsten; Editing by Nick Macfie)