Top US intelligence honchos warned Americans on Wednesday not to use smartphones made by Chinese makers Huawei or ZTE.

Despite the fact that US companies like Apple have long assembled their smartphones in China, a lineup of officials from the National Security Agency, the FBI and the CIA told lawmakers in a hearing that they think smartphones sold by the Chinese firms pose a security risk.

“We’re deeply concerned about the risks of allowing any company or entity that is beholden to foreign governments that don’t share our values,” FBI Director Christopher Wray said before the Senate Intelligence Committee.

Wray said smartphones and other communication technology could be compromised “to gain positions of power inside our telecommunication networks that provides the capacity to exert pressure or control over our telecommunications infrastructure.”

Wray also said the phones could be used to “maliciously modify or steal information” and “to conduct undetected espionage.”

Huawei quickly denied that their products represent a national security risk to the US.

“Huawei is trusted by governments and customers in 170 countries worldwide and poses no greater cybersecurity risk than any ICT vendor, sharing as we do common global supply chains and production capabilities,” a spokesperson for Huawei said in a statement, according to CNN.