Story highlights The victim was a man aged 19 or 20 from New Delhi, police say

The visitor "jumped into the tiger's enclosure," the zoo director says

Cell phone video appears to show the tiger grabbing the man by his neck, mauling him

A day out turned to tragedy Tuesday when a white tiger in a New Delhi zoo mauled a visitor to death, an official said.

The attack happened around lunchtime after the visitor "jumped into the tiger's enclosure," zoo director Amitabh Agnihotri told CNN.

At a police briefing on the case, Mandeep Singh Randhawa, a deputy police commissioner, said the victim was a man aged 19 or 20 from New Delhi.

Only his first name, Maqsood, has been released so far.

Local media earlier reported that he appeared to be a teenage schoolboy.

The tiger apparently grabbed the visitor by his neck, dragged him to a corner and mauled him, a cell phone video played out on local television networks showed.

Eyewitnesses who spoke with reporters gave a similar account of the attack and accused zoo security of a slow response.

"Instead of focusing on saving that person's life, the security was focusing on shooing away the crowds who had gathered there," an unnamed woman visitor said in televised comments from outside the zoo.