A U.S. Senate investigation has found that counterfeit Chinese electronic parts used in U.S. military equipment are compromising the safety of American troops and posing a national security risk.

A year-long investigation by the Senate Armed Services Committee found over 1,800 cases of fake electronic components in everything from cargo aircraft to night vision goggles.

The report released Monday said that more than 70 percent of an estimated one million suspect parts could be traced to China, which it says has failed to adequately police its counterfeit electronics market.

The investigation also criticized U.S. authorities and defense contractors for not being able to detect fakes or for routinely failing to report cases of suspected counterfeit parts.

The committee blamed Chinese officials for interfering with its investigation, saying U.S. investigators involved in the probe were denied visas and were told that a negative report could harm U.S.-China relations.

The report did not mention any specific cases where use of the counterfeit parts had caused damage or harmed lives. But it warned that the use of fake components in defense systems can compromise performance and reliability, risk national security, and endanger the safety of military personnel.