A white tiger has attacked and killed an Indian schoolboy at Delhi zoo, officials and witnesses say.

Zoo manager Riaz Khan said the teenager "seems to have leapt over the railing into the tiger enclosure", news agency AFP reported.

Television pictures showed the boy crouching against a wall while the tiger stood near him.

An eyewitness said the teenager was leaning over the barricade when he fell into the tiger's enclosure.

"Around 1.30 pm, we were in the reptiles area when we heard loud screams," eyewitness Himanshu told CNN-IBN news channel.

"I ran to the tiger enclosure where we saw that a white tiger had caught a boy by his neck and he was writhing in pain. Some children threw small sticks and stones at the tiger.

"The boy suffered for the next 10-15 minutes but nobody helped him," he added.

White tigers are a rare variant of the customary orange Bengal sub-species.

Considered an endangered species, they are found in south and east Asia, particularly India, and owe their colour to a recessive gene.

Source: BBC