Police believe the herd could have been upset by a train killing a baby elephant a few days ago.

Locals say the animals have developed a taste for locally-brewed rice beer and may have been drunk.

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The dead include four children, two of them two-year-old twins, police said. The twins' mother was also injured by the stampeding elephants.

About 60 elephants rampaged through a village at Tingri, near the Digboi oil refinery, 530kms (330 miles) east of the state capital Dispur.

Police say the most likely explanation for the elephants' behaviour is that Tingri is one of the nearest villages to where a baby elephant was knocked down and killed by a train, and this could have been a reaction.

Competition for food in the elephants' shrinking natural habitat could be another reason.

Sonadhar Doley, Assam's chief wildlife warden, said: "A shrinking habitat and a disproportionate increase in their numbers in the last decade have led to alarming behavioural changes in the elephants."

Another theory for the stampede is that the herd got drunk on rice beer.

Locals say elephants have developed a taste for the brew and can become unpredictable after drinking.

And wildlife officials have expressed concern over the elephants' new-found taste for "laopani" a locally-brewed rice beer.

But police say it is the least likely explanation for the stampede.

Forest officials have been sent to the area to chase out the elephants.