A city in southern China went ahead with an annual dog-meat eating festival Tuesday despite heavy criticism and protests from animal rights activists.

Vendors slaughtered dogs and cooked their meat in dozens of restaurants across the city of Yulin, in an event that has come to symbolize the cruelty and potential for spreading disease associated with the largely unregulated industry.

Activists bought dogs from dealers who had been planning to slaughter them, while local residents complained that outsiders were ruining what they consider a local tradition.

"We came to Yulin to tell people here dogs are our friends. They should not kill dogs in such a cruel way and many of the dogs they killed are pet dogs," said Yang Yuhua, a volunteer from the central city of Chongqing.

An estimated 10 million to 20 million dogs are killed for their meat each year in China, and the Yulin event has become a lightning rod for criticism.

Many of the dogs are believed to have been pets stolen from their owners or simply picked up off the street. They are stuffed in cages, and trucked to the city about 2,000 kilometers (1,250 miles) south of Beijing in the province of Guangxi, often without food or water.

Cats eaten at the festival are subjected to similar ill treatment.

The local government has in recent years sought to disassociate itself from the event, forbidding its employees from attending and limiting its size by shutting down some dog markets and slaughter houses.

"The so-called dog-meat eating festival has never been officially recognized by government or by any regulations or laws," said an official reached by telephone at the city government's general office.

"We hold meetings every time before the so-called festival, discussing counter measures such as deploying local police, business and sanitary authorities to inspect and deal with those who sell dogs," said the official, who like many Chinese bureaucrats would give only his surname, Liu, because he was not authorized to speak to reporters.

Opponents this year expanded their campaign to the United States, petitioning politicians in San Francisco to pressure their Chinese colleagues into calling for an end to the slaughter.

Actors and celebrities, including Matt Damon, Joaquin Phoenix and Rooney Mara, also released a public service announcement calling for an end to the torture and killing of dogs in China, South Korea and other Asian nations.

The brief clip focused particularly on the practice of killing dogs by beating, burning and other painful methods in the belief that dying by torture makes their meat taste better.

Such efforts may be having an effect. Wendy Higgins of the Humane Society International said activists on the ground reported fewer dogs killed and less visible dog meat eating than in years past.

The society "urges the Yulin authorities to take decisive steps to spare countless animals from a fate involving a brutal beating to death with metal poles," Higgins said in an emailed statement.

As many as 10,000 dogs are believed to be killed during the event, which falls around the summer solstice that arrived on Monday this year. Promoters say eating dog meat during the summer helps ward off the heat and maintain a healthy metabolism.

"It's been a tradition for years for us to celebrate the festival. We can't change it simply because they (animal lovers) love dogs," a local resident, who gave only his surname, Huang, told The Associated Press.

"They don't want us to eat dog meat. We eat dog meat to celebrate the festival, but since they've come here, they've ruined our mood completely," Huang said.

Opponents say the festival is cruel and has no redeeming cultural value.

Another animal rights activists, Chen Chun, said the push to end the Yulin festival was part of a larger campaign to pass legislation banning animal cruelty. A draft animal cruelty law remains mired in China's legislature and prosecution of dog thieves and those violating animal transport laws remains lax, activists complain.

"Our ultimate goal is that the country can make a law to protect animals, especially dogs here," Chen said.

Activists debated and argued with local residents, with police intervening at times to prevent any physical confrontations.

Activists said rallies held around the country to oppose dog eating, as well as outrage on social media from the growing ranks of dog lovers, are already having an effect. Dog meat restaurants have been forced to take the festival indoors and large-scale open air dog-meat consumption is no longer seen.

Along with the question of animal cruelty, dog meat also poses a risk to human health by spreading diseases such as trichinellosis, rabies and cholera, the Humane Society says.

Guangxi is already one of China's five worst areas affected by human rabies, and Yulin ranks as one of the top 10 Chinese cities in terms of cases, the organization says.