U.S. city Detroit filed for bankruptcy Thursday, making it the largest-ever municipal bankruptcy in U.S. history, local media reported.

Detroit, saddled with more than 18 billion U.S.dollars in debt, became the biggest U.S. city in history to file for bankruptcy. The 16-page petition was filed in U.S. Bankruptcy Court in Detroit.

Michigan Governor Rick Snyder authorized Kevyn Orr, Detroit emergency manager, to file for federal bankruptcy, saying "it is clear that the financial emergency in Detroit cannot be successfully addressed outside of such a filing, and it is the only reasonable alternative that is available."

Kevin Orr, a bankruptcy expert, was hired by the Michigan state in March to lead Detroit out of a fiscal free-fall and made the filing in federal bankruptcy court. Snyder's office was making plans to hold a Friday morning news conference at the Maccabees Building, Midtown, where the governor declared a financial emergency for Detroit on March 1.

If the bankruptcy filing is approved, Detroit city assets could be liquidated to satisfy demands for debts payment.

According to NBC News, a number of factors, notably steep population and tax base falls, have been blamed on Detroit's tumble toward insolvency. The population of Detroit that in the 1950s reached 1.8 million is now struggling to stay above 700,000. Much of the middle-class and scores of businesses have fled Detroit, taking their tax dollars with them.