A group of bears at an animal park in Shanghai mauled an employee to death as visitors watched in horror from a tour bus.

The incident at Shanghai Wild Animal Park was recorded Saturday by panicked onlookers, some of whom posted footage on China’s popular Weibo platform. Witnesses inside the bus could be heard shrieking, “There seems to be a man” and “What’s going on?” the BBC reported Monday.

The park activated emergency protocols and temporarily closed the area as officials attempted to find out what happened to the worker inside the zoo’s beast-of-prey zone, which is accessible to tourists who remain inside designated vehicles.

Although details of the attack were scarce, park officials said they are working with investigators.

Officials said in a statement that they were “extremely heartbroken” and offered their sympathy to the family of the victim, who was not publicly identified. Officials also apologized to the guests who saw the attack.

Black and brown bears of all sizes roam freely in the drive-through area, which was designed to mimic their original habitat, according to the park’s website. Video footage posted to Instagram days before the attack shows one bear climbing up the side of a tourist bus as those inside stuff carrots into its mouth.

“Dangerous! Keep away!” a sign inside the vehicle reads.

The park spans almost 400 acres and is home to an estimated 10,000 exotic animals, including zebras, flamingos, giant pandas and tigers.

Park officials said they vowed to learn lessons from the attack.

Animal rights activists have long called for animals kept in wildlife parks, sea-life centers and zoos to be released. People for the Ethical Treatment of Animals (PETA) Asia said the incident in Shanghai was unsurprising.

“How many more people have to be hurt or killed by wild animals kept in confinement before we accept that these animals do not belong in captivity?” the group said in a statement to The Washington Post. The statement added that “no amount of time” spent in a zoo, cage or marine park would erase the predatory instincts of animals taken from the wild.

“This incident illustrates the profound level of stress, anxiety, and agitation that these animals experience every day of their lives,” the organization said as it called for tourists and families to stop visiting establishments that detain animals for profit and entertainment.

Despite its promise to visitors of a “magical experience” and “amazing performances,” the park has frequently made headlines for the way it treats its animals.

In 2013 a video went viral after a bear pounced and attempted to mutilate a monkey during a bicycle race at the park’s “Animal Olympics” event. Both animals had fallen off their bicycles, and crowds could be heard gasping as staff members brandished sticks to try to free the monkey from the bear’s clutches.

The incident was called “cruel” and sparked calls for such events to be banned.

The zoo responded to the criticism by saying that the bear was wearing a muzzle and that the monkey survived the attack.

Three years later, a video emerged appearing to show a worker at the park slapping the face of a tiger cub in a bid to get it to pose for photographs with visitors; that footage also triggered widespread condemnation and led to calls for the venue to be closed.

In 2017, the park was included on the South China Morning Post’s list of “terrible zoos,” which highlighted concerns about poor conditions for animals in captivity. The report claimed that staff members at the park in Shanghai had been photographed riding ostriches and forcing elephants to dance for entertainment and said that at least five pandas at the facility had died as a result of infection and organ failure.

Gerry Shih in Taiwan contributed to this report.

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