American-made devices used for Internet monitoring have been detected on government and commercial computer networks in Iran and Sudan, in apparent violation of U.S. sanctions that ban the sale of goods, services or technology to the autocratic states, according to new research.

Several of the devices, manufactured by California-based Blue Coat Systems, were also discovered in Syria. Although Blue Coat tools have been identified in Syria in the past, the new research indicates that the government of President Bashar Assad has more of the monitoring devices than previously known.

Experts say that in Syria, Blue Coat's tools have been used to censor websites and monitor the communications of dissidents, activists and journalists. In Iran and Sudan, it remains unclear exactly how the technologies are being used, but experts say the tools could empower repressive governments to spy on opponents.