Nine Chinese companies, including Alibaba, Tencent and Sina, jointly issued a proposal to "say no to illegal wildlife and its products" at a seminar on Friday in Hangzhou, Zhejiang province.

The Internet giants vowed to enable no advertising or trade in illegal wildlife and its products on their platforms and said they would voluntarily accept supervision from the society and government.

They also appealed to more enterprises to join them and called on the public to boycott buying illegal wildlife or its products.

The seminar was held by the National Endangered Species Import and Export Management Office with China Wildlife Conservation Association and other organizations including Wildlife Conservation Society and The Nature Conservancy.