The Chinese government has frequently hacked into the computer systems of defense contractors for the U.S. Transportation Command, the Pentagon agency responsible for deploying American troops and military equipment worldwide. A bipartisan Senate investigation found that in one year, from June 1, 2012, through May 31, 2013, the Chinese government had gained access to sensitive U.S. defense logistics information at least 20 times, but that the Transportation Command, known as TRANSCOM in military circles, was aware of only two of the security breaches.