Members of Austria's elite Cobra police commando unit have been assigned to protect the left-leaning candidate for Austria's presidency in response to death threats from right-wing extremists.

Upgraded security for Alexander Van der Bellen was reported Wednesday by Austrian newspapers and confirmed by a government official who requested anonymity because he was not authorized to divulge the confidential measures.

Van der Bellen and right-winger Norbert Hofer face off Dec. 4 in elections postponed from this month after the discovery that some envelopes for absentee ballots would not seal properly.

Van der Bellen narrowly won voting for the post in May. But those results were declared invalid by Austria's highest court, which ruled in favor of claims of widespread irregularities by Hofer's anti-immigrant and euroskeptic Freedom Party.