At least 35 people have been killed in an attack in Istanbul

People flee as ambulances are on the attack site on January 1, 2017 in Istanbul. Photo: Ihlas News Agency/ AFP /Getty Images.

A gunman has killed at least 35 people and wounded 40 others after opening fire in a nightclub in Istanbul during New Year’s celebrations.

Istanbul’s governor said the attacker, believed to have been dressed in a Santa Claus costume, shot at police outside the nightclub before entering.

More than 500 people were inside the club at the time.

Local media reports say more than one assailant may have been involved in the attack and may still be inside the nightclub.

Police have cordoned off the area and an operation is ongoing.

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