Police officers stand guard near the site of a terror attack at a night club in Istanbul, Turkey, Jan. 1, 2017. Thirty five people were killed and 40 others wounded in a terror attack on a popular night club in Istanbul early Sunday morning, Istanbul's governor said. (Xinhua/He Canling)

ISTANBUL, Jan. 1 (Xinhua) -- Thirty-five people were killed and 40 others wounded in a shooting attack on a popular nightclub in Istanbul early Sunday morning, said Istanbul governor Vasip Sahin.

Sahin said the terror attack was carried out by one single gunman.

A security analyst, who declined to be named, told Xinhua that the attacker killed the security guards before storming into the club, which reportedly gathered as many as 400 for New Year celebration.

The analyst said the gunman changed his ammunition clip several times in the shooting spree.