Alalam - Turkey

New Year's revellers fled for their lives when the gunman opened fire at a nightclub in Istanbul, Turkey.

Witnesses said they dived under the tables at the Reina nightclub and even into the Bosphorus river.

Now a massive security operation is underway to track down the killer and any co-conspirators.

He's a member of the East Turkestan branch of ISIS, according to Turkish media reports.

He's described as being from being from East Turkestan, Afghanistan or Chechnya.

However, authorities still do not know his name or precise nationality.

Blame for the attack has variously been placed with ISIS and Kurdish militants.

No one has yet claimed responsibility, but the leader of Kurdistan Workers’ Party denies involvement.

The attack comes only days after a pro-ISIS group called for attacks by "lone wolves" on "celebrations, gatherings and clubs".

A witness from Lebanon who gave her name as Hadeel described the carnage in the Reina nightclub as the gunman unleashed his massacre.

"At first we thought some men were fighting with each other," she said. "Then we heard the sound of the gunfire and ducked under the tables.

We heard his footsteps crushing the broken glass.

"We got out through the kitchen, there was blood everywhere and bodies."

SA