More than a million counterfeit parts for U.S.-made equipment and weapons are in circulation, the report by the Senate Armed Services Committee said.

It cited defense equipment from Raytheon Co., L-3 Communications Holdings Inc. and Boeing Co., including aircraft deployed to Afghanistan, among recipients of spares usually manufactured in China.

The fakes put U.S. lives at risk, said the 112-page report, which accused the Defense Department of not doing enough to learn about the dangers posed to U.S. military personnel by counterfeit components.

The committee, led by Democratic chairman Carl Levin and Republican John McCain, spent more than a year preparing the report but it was thwarted in efforts to obtain visas to investigate fakes said to have been manufactured in China.

Chinese government officials say Beijing takes seriously any allegations of counterfeit defense production in the country and is prepared to stamp out makers of any contraband defense spares if found.

Reports of a thriving global business in "alternative" spare parts for U.S. defense equipment have circulated for more than a decade, been the subject of publications and television programs.

The report cited how "this flood of counterfeit parts, overwhelmingly from China, threatens national security, the safety of our troops and American jobs."

Fake components were found in missile parts, memory chips, night flight operations, C-17 Globemaster III and C-130J tactical transport planes, Boeing aircraft modified for anti-submarine and other equipment used by U.S. forces in operations in Afghanistan and elsewhere.

The report claims its investigations uncovered 1,800 cases of bogus parts, including those on the special operations helicopters and U.S. Navy surveillance planes.

Placing the blame squarely on China, the report claims the finding "underscores China's failure to police the blatant market in counterfeit parts -- a failure China should rectify."

Analysts said the long-drawn controversy over fake space parts indicates the difficulty of ensuring fakes are eliminated from the parts marketplace. The expertise and equipment required to vet each and every part obtained on the market will add costs that few defense operations can afford.

The market for contraband defense material has also developed in response to demand from countries that originally received U.S. defense equipment and weapons, including Iran and Venezuela, but are no longer on friendly terms with Washington.

In some respects manufacturers of fake spares can be expected to be cynical enough to test the markets with their wares and to hone their skills and improve the quality of their fakes, analysts said.