ISTANBUL - The Islamic State terror group is claiming responsibility for the mass shooting at a nightclub in Istanbul on New Year's Eve.

Surveillance video shows the moment the gunman stormed the crowded club on Sunday night.

He opened fire with an automatic weapon, killing 39 people and wounding nearly 70 others.

Early reports said the shooter was dressed as Santa Claus, but authorities later confirmed that was not the case.

The gunman was still at large as of Monday.