Police are investigating a safari park after a zookeeper was today eaten alive by lions - which now face being put down.

The beasts pounced on Jian Rangkasamee, 59, when he stepped out of his jeep to pick up rubbish from the floor in the open enclosure at Safari World in Bangkok at around 11 am local time.

Shocked visitors screamed as the predators pinned down their victim.

Onlookers, including a number of zoo workers, could only sound their horns in a futile attempt to scare away the sub-Saharan big cats as they feasted on human flesh.

Officials arrived with guns, which caused the lions to scatter, but the zookeeper was already mauled to death as the lions gnawed his body until the bones were exposed.

Zoo staff eventually drove the lions away and closed the drive-through area, where a puddle of blood could be seen on the ground. His mangled corpse was x-rayed.

Hospital staff said Jian had suffered multiple broken bones and the 'majority of his flesh was damaged or missing'.

Police and government officials visited the park, which was closed down as managers said they would consider whether to kill the lions that attacked the worker.

Colonel Niruchpol Yothamat, superintendent of Khannayao district station, said he inspected the scene of the death for evidence. Zoo officials are also checking if the lions that killed Jian and said they would be put down if they are found to be dangerous.

He added: 'The victim was a supervisor aged 58 who had worked for around 30 years, chasing animals when they came out of their enclosure. Normally, he would remain in the vehicle because the sound of the engine would deter lions away.

'However, the incident occurred because he got out from the driver's side, as we still found his shoes at the scene. Currently, we have not received a report that he has passed away.'

The zoo employee responsible for the area where the incident occurred said: 'The incident occurred when he was performing a task inside the cage. Here, we have a rule prohibiting both customers and employees from leaving the vehicle.

'After hearing the horn, we quickly rescued him. We did not know how it happened or why he left the vehicle. Each employee has their own vehicle, and he was in charge of the animals at the entrance.

'We review our rules and safety measures daily because we work with dangerous animals. We have been open for 40 years and have never experienced an incident like this.

'There were five lions at the scene, out of a total of about 32 in the entire zoo, all of which are licensed. We have tens of thousands of animals, including lions of different species, mostly native to Africa and all named. We will investigate further to determine what happened.

'If the lions that killed our staff member are found to be dangerous, they will be humanely destroyed. It is not normal for them to attack a keeper.'

Eye-witness Professor Tavatchai Kanchanarin, a doctor at a leading hospital who was visiting at the time, described the horror attack.

He said: 'The lion attacked the zookeeper while he was getting out of his car. It was about 10 metres away, then slowly approached and grabbed the zookeeper from behind, dragging him to the ground and biting him.

'Three or four other lions then joined in with biting the zookeeper.

'Many people witnessed the incident but didn't know how to help. They honked their own car horns and shouted for help.

'At first, I assumed it was familiar to the zookeepers, as the person who was bitten might have been a lion keeper. I thought the lions were trying to hug him, so no one went near that area.'

The professor said the attack continued for around 15 minutes before zoo staff were able to reach the victim. He was rushed to the hospital but was pronounced dead upon arrival.

Owners at the Bangkok World Safari Park have yet to comment on the incident. Local media reported that the attack happened outside of feeding hours for the lions.

The victim, Jian, was reportedly an experience conservationist who had worked at the safari park since April 2019.

A spokesman for the government's Department of National Parks, which is responsible for zoos, said staff were on their way to the facility to check on the animals and the safety measures in place.

The park is best known for its orangutan that hugs and gropes female visitors as they pose for pictures.

However, the attraction has attracted criticism from animal rights groups such as PETA, who claim the ape is subject to poor treatment while being 'humiliated and exploited'.