From the House Permanent Select Committee on Intelligence report,
Investigative Report on the U.S. National Security Issues Posed by Chinese Telecommunications Companies Huawei and ZTE:
I. The threat posed to U.S. national-security interests by vulnerabilities in the telecommunications supply chain is an increasing priority given the country’s reliance on interdependent critical infrastructure systems; the range of threats these systems face; the rise in cyber espionage; and the growing dependence all consumers have on a small group of equipment providers.
A. China has the means, opportunity, and motive to use telecommunications companies for malicious purposes.
B. Suggested “mitigation measures” cannot fully address the threat posed by Chinese telecommunications companies providing equipment and services to United States critical infrastructure.
The full report is actually a pretty good read.