The report this week from the University of Toronto's Citizen Lab said devices from California-based security firm Blue Coat Systems were being used in China, Russia, Venezuela and other countries with "a history of concerns over human rights."

"Our findings support the need for national and international scrutiny of Blue Coat implementations in the countries we have identified, and a closer look at the global proliferation of 'dual-use' information and communication technologies," said the report.

"Internet service providers responsible for these deployments should consider publicly clarifying their function, and we hope Blue Coat will take this report as an opportunity to explain their due diligence process to ensure that their devices are not used in ways that violate human rights."

The Citizen Lab report said several weeks of scanning and analysis that ended in January 2013 uncovered 61 Blue Coat ProxySG devices and 316 Blue Coat PacketShaper appliances "with specific functionality permitting filtering, censorship, and surveillance."

It said the devices were found in Egypt, Kuwait, Qatar, Saudi Arabia, the United Arab Emirates, Afghanistan, Bahrain, China, India, Indonesia, Iraq, Kenya, Lebanon, Malaysia, Nigeria, Russia, South Korea, Singapore, Thailand, Turkey, and Venezuela.

The new report comes after Blue Coat technologies were discovered in Syria in 2011 being used for Internet filtering and monitoring.

The company did not immediately respond to an AFP query on the Citizen Lab report.

In 2011, it issued a statement claiming its devices ended up in Syria after an "unlawful diversion" and that its appliances "are not intended for surveillance purposes."

The company's website says it "offers solutions that provide the visibility, acceleration and security required to optimize and secure the flow of information to any user, on any network, anywhere."