Warning: This story contains graphic imagery some may find disturbing.

It’s a practice that makes animal-lovers ill — China’s so-called Yulin Summer Solstice Lychee and Dog Meat Festival for which some 10,000 canines are said to be beaten, killed and cooked for human consumption. Cats too. Traditional lore says eating dog meat brings good luck and health. But the event, which has ignited fury for years, is gaining momentum on social media.

The annual event in Yulin in China’s Guangxi region marks the summer’s start, which will be June 22 this year.

Indeed, eating dog meat is legal in China, but canines are supposed to be raised on farms and certified for human consumption before they are sold. Animal rights advocates say dogs in Yulin are stolen from farms and family homes — many still wearing collars when they are killed. Aside from animal cruelty issues, they say, such festivals fuel crime and food safety concerns.

Mounting pressure from animal rights groups ignited uproar last year, prompting nationwide protests.

Amid outcry, Yulin’s government banned public slaughter and advertising using words “dog meat,” though it claimed that although locals had held small get-togethers in the past, the city-wide festival was a myth.

“The so-called summer solstice lychee dog meat festival does not exist,” the government said in a statement, according to Time. “Neither Yulin government nor social organizations have ever held such activities.”

The state news agency Xinhua said last year the festival is “only a local folk custom, without official sanction.” But locals say now, instead of slaughtering dogs in the streets, they do it in secret.

“Now we have to do it as though we are thieves,” a local restaurant owner told a Chinese TV station, according to the Associated Press.

This year, social media has pushed the protests forward.

Animal rights advocates say dogs are caught with nets, drugged or poisoned and kept in pins until they are killed for their meat.

The past month, there have been nearly a million tweets from people using the hashtag #StopYulin2015. This week, British comedian Ricky Gervais, who has partnered with Humane Society International, wrote: “Please help our best friend. #StopYuLin2015.” He attached a photo of a dog with a lipstick kisses on its face, saying: “The only marks you should leave on a dog.”

As of Thursday, Hong Kong-based animal rights group Animals Asia said its recent letter urging the country’s dog meat traders to boycott the festival had garnered about 70,000 signatures.

The U.S.-based animal rights organization Duo Duo Animal Welfare Project has launched an online petition, calling on Yulin Governor Chen Wu to cancel the event, citing issues ranging from animal cruelty to social stability to food safety. So far, it has more than 700,000 signatures. The group also posted a video on YouTube, which has been viewed nearly 500,000 times.

“I went to a slaughter house in Yulin a few days ago,” Duo Duo founder Andrea Gung told BBC News earlier this month. “The dogs and cats were wearing collars and of different sizes and breeds.”

Peter Li, associate professor of East Asian politics at the University of Houston-Downtown and a China policy adviser with Humane Society International, wrote in the South China Morning Post that he visited Yulin just last month.

“What I saw was a city in preparation for the annual massacre,” he wrote. “A slaughterhouse at the city’s Dong Kou market had just received a new supply of dogs shipped from Sichuan. The unloaded dogs looked emaciated, dehydrated and terrified. Inside two other slaughterhouses hidden in residential areas not far from the market, dogs and cats, many wearing collars, displayed behavior associated with household pets.

“The slaughter is more than an insult to the nation’s expanding animal-loving community.”

Among the most serious issues, advocates argue, is the heightened risk of rabies.

Worldwide, China is ranked the second-highest for the number of people who contract rabies and the Guangxi province has the most cases in the country, CNN reported, citing China’s ministry for public health. Yulin is branded one of the country’s “top ten cities” for rabies cases among humans.

“This is more than an animal welfare issue,” Li told the New York Times. “This is a matter of public health as well. After long-distance transport, most of the dogs are sick, dying or already dead. Skin problems are common. These are serious food safety problems and public health hazards.”

Dog meat was once considered a delicacy in China. Yulin’s festival started in 2009 or 2010, according to media reports, to help dog meat traders boost business.

In China, people have come out on both sides of the debate. On the Chinese social media site Weibo, some have spoken out against consuming what Westerners consider household pets, according to BBC News, while others said the country’s local customs should be respected.

Yulin’s food and drug administration has vowed to crack down on the festival this year, Beijing-based animal rights lawyer An Xiang said, according to the New York Times. He filed a petition earlier this year to force the government to make its dog meat regulations public information.

“I believe the Yulin authorities are in hot water now,” Li told the newspaper. “I believe the legal team led by An Xiang knows what to do next. Let’s see.”

Disclaimer: Some of the following images were taken by the Associated Press for Humane Society International.