By Geeta Pandey
BBC News, Delhi
Indian tiger skins are openly bought and sold on the streets of China, two leading conservation groups warn.
Many people in China use animal skins for clothing
The animal is protected under the UN convention on international trade in endangered species - to which both India and China are signatories.
The agencies say their investigation has discovered that all the skins on sale in China come from India.
Wildlife activists say if immediate action is not taken to save the tiger it could soon become extinct in India.
The Environmental Investigation Agency and the Wildlife Protection Society of India say that much selling goes on in the Tibetan Autonomous Region.
They screened a video of the investigation - shot at major festivals in August - at a press conference in Delhi.
The video showed images of Tibetan officials, a school teacher and even children wearing clothes made out of the tiger skin.
"It's not another tiger crisis, it's the final one," Belinda Wright, head of the Wildlife Protection Society of India, said.
In the video, Ms Wright is shown visiting various shops which openly display and sell tiger skins.
She is told by traders that all the tiger skins come from India.
Rampant poaching of the animal has resulted in an alarming reduction in the number of big cats in the country's reserves.
Indian prime minister, Manmohan Singh, set up a task force after reports earlier this year that the entire tiger population of Sariska reserve in Rajasthan had been wiped out by poachers.
Wildlife activist Valmik Thapar, a member of the tiger task force, said he was shocked by the footage.
"I didn't know about the scale of the trade. This is shocking, absolutely shocking."
A century ago there were around 100,000 tigers across Asia. Today, there are fewer than 5,000 in the world and half of them live in Indian forests.
Alarmed wildlife activists say the tiger population is not sustainable at this rate and they have called for immediate action from the government of India.
They say the tiger skins and bones are mostly smuggled into China through Nepal and have called for tripartite talks between the three countries.
During the course of the investigation, Ms Wright said, they counted 83 tiger skins.
"No tiger will be left here unless India and China work hand-in-hand," she said.
Recently, the United Nations also issued an appeal asking the Indian government to take steps to save its tigers.