Cooked dogs are displayed at a vendor's stall in Yulin, in southern China's Guangxi province early on June 22, 2015.

The city holds an annual festival devoted to the animal's meat on the summer solstice which has provoked an increasing backlash from animal protection activists.

Vendors wait for buyers next to the dogs in cages for sale at a market ahead of a dog meat festival in Yulin in south China's Guangxi Zhuang Autonomous Region, Monday, June 20, 2016.

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.

Vendors wait for customers to buy dogs in cages at a market in Yulin, in southern China's Guangxi province on June 21, 2015.

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.

Animal-loving Yang Xiaoyun (C) goes around buying some 100 dogs at a market in Yulin, in southern China's Guangxi province, to rescue them, June 20, 2015.

Yang has paid more than 1,000 USD to prevent around 100 canines from being eaten ahead of a dog meat festival which has provoked outrage worldwide.

A woman eats dog meat at a gathering with her friends to celebrate the upcoming local dog meat festival in Yulin, Guangxi Autonomous Region, June 21, 2015.

Local residents in Yulin host small gatherings to consume dog meat and lychees during the festival, which falls on Monday this year, in celebration of the summer solstice.

An animal rights activist looks at a dog as she negotiates a price with a vendor to rescue it from dog meat dealers at Dashichang dog market in Yulin, Guangxi Autonomous Region, June 21, 2015.

In the market, some dogs are sold as pets while others are sold for dog meat.

A dog, purchased by animal right activists to rescue it from dog meat dealers, is kept in a temporary shelter prior to a local dog meat festival in Yulin, Guangxi Autonomous Region, June 21, 2015.

Animal rights activist Du Yufeng is asked to leave by a policeman after she attempted to protest against eating dog meat as local residents follow behind at a dog meat restaurant district on the day of the local dog meat festival in Yulin, Guangxi Autonomous Region, June 22, 2015.

For many residents of China's southern town of Yulin, the peak of summer is the time to get together with family and friends - and consume copious amounts of dog meat.

Thousands of dogs end up on the chopping block during the festival, which has become increasingly controversial in China.

An animal rights activist leads dogs away from a market after she bought them from dog vendors during a dog meat festival in Yulin in south China's Guangxi Zhuang Autonomous Region, June 21, 2016.

Dogs rescued by animal right activists from dog meat dealers are kept in a temporary shelter in Yulin, Guangxi Autonomous Region, June 21, 2015.

People eat dog meat at in the dog meat restaurant district in Yulin, Guangxi Autonomous Region, June 22, 2015.

Animal activists hold banners reading "Stop to dogs' massacre in China" against Yulin Dog Meat Festival in front of the Chinese embassy in Rome, Italy June 21, 2016.

In 2016, opponents 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.

Sandi Thom, Lucy Watson, actress Carrie Fisher, Marc Abraham, Jenny Seagrove and Anneka Svenska attend a photo call as campaigners submit an 11 million signature petition calling for an end to China's Yulin dog meat festival at the Chinese embassy in London on June 7, 2016.

In 2016, opponents 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.

Customers drink over dog meat dishes as they gather to eat dog meat and lychees as part of the upcoming dog meat festival at a restaurant in Yulin, Guangxi Autonomous Region, June 21, 2015.

People eat dog meat at a restaurant during the local dog meat festival in Yulin, Guangxi Autonomous Region, June 22, 2015.

In 2016, 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.