Two key members of the Senate Armed Services Committee are demanding China crack down on firms that make counterfeit military parts, saying they jeopardize U.S. national security and American lives.

Democrat Carl Levin and Republican John McCain say fake electronic military hardware has wound up in U.S. helicopters and cargo jets.

A Commerce Department investigation says more than 70 percent of counterfeit parts it found were traced to China. The rest came from Britain and Canada.

The investigators say in most cases, used electronic parts were disguised and resold as new.

Along with demanding China and others take action, Senators Levin and McCain are also pushing the Pentagon to enforce laws designed to protect the nation's military parts supply chain.

The Armed Services Committee – which has jurisdiction over research and development of weapons systems, defense policy, and the military – holds a hearing Tuesday in Washington on the issue.