House Intelligence Committee Chairman Mike Rogers (R-MI) and Ranking Member Dutch Ruppersberger (D-MD) on Oct. 8 published an investigative report raising concerns about two of China’s largest telecommunications firms, Huawei and ZTE, for continuing to conduct business with Iran.

Consistent with a hearing held by the committee earlier this year, the investigation revealed that neither company cooperated fully with the inquiry into matters such as contracts with Iran for training and maintenance of surveillance equipment.

This led the committee to “further doubt their ability to abide by international rules,” including U.S. sanctions against Iran.

While Huawei acknowledged that is scaling back its business with Iran, ZTE did not provide any details regarding an internal review to determine if the company destroyed evidence relating to its Iranian operations.

Shortly after the committee issued its findings, Cisco Systems, one of the world’s largest suppliers of computer networking equipment, announced it was cutting ties with ZTE since it violated U.S. sanctions by selling Cisco products to Iran.