PRAGUE (AP) — The Czech Republic’s cyber security watchdog is warning against the use of products by Chinese electronics giant Huawei and another Chinese telecommunications company, ZTE.

The National Cyber and Information Security Agency said Monday that their software and hardware pose “a security threat.”

Huawei is the biggest global supplier of network gear for phone and internet companies.

It has become the target of U.S. security concerns because of its ties to the Chinese government. The U.S. has pressured other countries to limit use of its technology, warning they could be opening themselves up to surveillance and theft of information.

A Czech spy agency recently warned against the activities of Chinese spies on Czech territory.