Amnesty International says China is fueling global human rights abuses by manufacturing and exporting equipment used by police for torture.
In a report Tuesday, Amnesty said a rising number of Chinese companies are profiting from the trade of the so-called "tools of torture," which include electric shock stun batons, metal-spiked batons and weighted leg cuffs.
The London-based group says 130 mostly state-owned Chinese companies now produce and trade the equipment. That is up from just 28 a decade ago.
Amnesty said Chinese authorities have "done nothing" to prevent the tools from being sent to countries in the Middle East, Africa and Asia where authorities "persistently abuse human rights."
China has not responded to the report, which was produced with the help of the Omega Research Foundation.
The report said many of the tools are legitimate when used properly, while others are "intrinsically cruel and inhumane" and should be immediately banned.
China is the world's only known manufacturer of spiked batons, which Amnesty said are "specifically designed as implements of torture and can cause significant pain and suffering."
It said at least 29 Chinese companies also produce "inherently cruel" electric stun batons, which can be used to apply excruciating shocks to sensitive areas such as the genitals, throat or face without leaving physical traces.
The report also criticized the trade in abusive restraint devices, including heavy weighted leg cuffs and rigid restraint chairs that have been denounced by the U.N. Committee against Torture.
Amnesty says the tools are not only being used abroad, but also in China, where it says torture, ill-treatment, and the arbitrary use of force remain widespread. China explicitly bans torture. It denies the practice is widespread in the country.