Shocking footage shows a crazed circus bear savaging its trainer just metres away from horrified kids as families run away in terror.

The performing bear is seen going wild in a Russian circus ring, attacking the man as children scream in fear.

The footage begins with the brown bear being forced to push a wheelbarrow while walking on its hind legs, The Sun reports.

But the muzzled beast suddenly turns on its trainer, knocking him down and leaping on top of him.

Children sitting just metres away — with no protective barrier — scream as another circus employee repeatedly boots the bear as it mauls his colleague.

When that failed to stop the 270kg animal, it was electrocuted with an electric shock device as the audience fled for the only exit in the travelling circus’s big top.

The trainer floored by the bear was understood to be injured but no further details of his condition were given to local media.

“My knees are still trembling,” said mum-of-one Galina Gurieva, 27, who filmed the distressing scene in the town of Olonets, north-east Russia.

“I was shocked there was no fence for the safety of spectators, given the size of the bear.”

Another parent said: “The spectators rushed outside in panic, including me.”

One visitor posted on social media: “It was an enormous bear, and they lost control of him.”

“At first, everyone thought it was a script,” someone else said. “But when the assistant started kicking the bear and pulled out the shocker, the panic started.

“People got up and ran to the exit.”

After the bear had been shocked into submission, the animal was said to be in a “frenzied state in the arena, terrifying the people”.

The bear was the star attraction at the Anshlag Tent Circus and this performance was billed as “Bow-legged and the Wheelbarrow”.

“We expected to see cute cubs and they brought in a huge grizzly-terminator,” a dad at the show said.

“They did not protect children and adults from possible attack.”

Police and safety officials are investigating the incident.

Travelling circuses with live animal performances remain popular in Russia despite growing campaigns for bans or curbs on such events.

This article otiginallty appeared on The Sun and was reproduced with permission