The Pentagon has failed what is being called its first-ever comprehensive audit, a senior official said on Thursday, finding U.S. Defense Department accounting discrepancies that could take years to resolve. Results of the inspection - conducted by some 1,200 auditors and examining financial accounting on a wide range of spending including on weapons systems, military personnel and property - were expected to be completed later in the day. We failed the audit, but we never expected to pass it, Deputy Secretary of Defense Patrick Shanahan told reporters, adding that the findings showed the need for greater discipline in financial matters within the Pentagon. It was an audit on a $2.7 trillion dollar organization, so the fact that we did the audit is substantial, Shanahan added. The U.S. defense budget for the 2018 fiscal year that ended on Sept. 30 was about $700 billion. He did not provide a figure detailing how much money was unaccounted for in the audit. Some of the compliance issues are irritating to me, Shanahan added. A 1990 federal law mandated that U.S. government agencies be audited, but the Pentagon had not faced a comprehensive audit until this one was launched in December. Defense officials and outside experts have said it may be years before the Pentagon is able to fix its accounting gaps and errors and pass an audit.