NSA intercepted international shipments of computer hardware

The NSA has been intercepting shipments of routers, switches and servers in order to hide their surveillance equipment, according to the people who exposed the agency's secret Prism spy project.

Journalist Glenn Greenwald made the revelations to a number of news sources while promoting his new book "No Place to Hide", which details more of the state secrets Edward Snowden revealed to him.

A June 2010 report from the head of the NSA's Access and Target Development department explains how the NSA would intercept packages, he alleges. The agency would then install surveillance equipment before resealing the packages so the changes were undetectable. The shipments would then be sent abroad.

When the equipment was finally received and installed it would then connect back to the NSA. The report states: "In one recent case, after several months, a beacon implanted through supply-chain interdiction called back to the NSA covert infrastructure. This call back provided us access to further exploit the device and survey the network."

The Guardian reports that for years the US government had warned companies not to trust Chinese routers manufactured by companies such as ZTE and Huawei because they "are built with backdoor surveillance functionality that gives the Chinese government the ability to spy on anyone using them."

The committee behind the claims explained that "private-sector entities in the United States are strongly encouraged to consider the long-term security risks associated with doing business with either ZTE or Huawei for equipment or services. Based on available classified and unclassified information, Huawei and ZTE cannot be trusted to be free of foreign state influence and thus pose a security threat to the United States and to our systems."

This led to Huawei eventually abandoning the US market. If Greenwald's claims are true, it now seems the US government was doing exactly the same.