Huawei Technologies Co. and ZTE Corp., China's two largest phone-equipment makers, provide opportunities for Chinese intelligence services to tamper with U.S. telecommunications networks for spying, according to a congressional report to be released today.

The House intelligence committee report says the two companies failed to cooperate with a yearlong investigation and to adequately explain their U.S. business interests and relationship with the Chinese government, according to a draft provided by the panel.

"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," says the report from the committee's chairman, Michigan Republican Mike Rogers, and its top Democrat, Maryland Representative C.A. "Dutch" Ruppersberger.