Dozens of endangered animals were seized as part of a joint operation by Interpol and the World Customs Organization, officials announced Tuesday. 

The seizures came as a result of more than 500 worldwide arrests throughout October, the agencies said in a joint news release, and more than 2,000 confiscations of protected animals and plants as part of an action called “Operation Thunder,” an annual joint operation that combats wildlife crime. Officials in 133 countries worked together, the agencies said in the release, making it the largest such effort since the annual operation began in 2017. 

Officials seized more than 1,370 live birds, a pangolin, two capped langur primates, two golden-handed tamarins, 53 other primates and thousands of turtle eggs, as well as 660 pounds of ivory, 30 tons of plants, dozens of big cat body parts and rhino horns, and more. Some of the items were smuggled in suitcases or passenger items, while others were transported through vehicles, boats and cargo transporters, the agencies said. 

The plants and animals are protected under a treaty called the Convention on International Trade in Endangered Species, or CITES, which was adopted in 1963 and protects endangered wildlife from illegal trade. Any trade performed “in breach of” the treaty is illegal, the agencies said. 

The agencies said that results from the arrests are still coming in, but preliminary information shows that 60% of the cases were linked to international organized crime groups, which used “high levels of document fraud” to transport many of the items and animals. The operation also found that protected reptiles and marine life were being “exploited for luxury brand fashion,” while online platforms were being used to sell some of the illegal goods. 

“Important and endangered animals, birds and plants are being put at risk of extinction by wildlife and timber traffickers. These appalling crimes not only deprive the world of unique animals and plants but also countries of their natural assets and resources,” said Jürgen Stock, the secretary general of Interpol. “The costs to communities are even greater … almost all environmental crime has links to other forms of crime including violence, corruption and financial crime.”