Troubled Italian bank Monte dei Paschi di Siena will need more rescue money than previously expected, according to calculations by the European Central Bank, potentially complicating the government's rescue efforts. The ECB, the main regulator for banks in the eurozone, has estimated the capital shortfall at 8.8 billion euros ($9.2 billion), according to a statement issued late Monday by Monte dei Paschi. The figure is well above the 5 billion euros that Monte dei Paschi had set as its capital increase goal, due to the fact that its capital position has deteriorated in the past month, apparently as customers withdrew deposits. Monte dei Paschi, Italy's third-largest bank, said it was asking the ECB for details of how it arrived at the higher figure. The bank's shares remained suspended from trading Tuesday at the request of Italy's stock market regulator. The Italian government on Friday said it was guaranteeing all of the bank's retail customers with part of a 20 billion-euro fund approved by parliament to ensure the stability of banks. Monte dei Paschi raised only about half of the capital independently. The Italian financial daily il Sole 24 Ore reported Tuesday that the government would invest 6.3 billion euros to prop up the bank. The rest would come from bondholders who would take losses under new EU rules meant to spare taxpayers the cost of rescuing banks. Monte dei Paschi was forced to raise new capital after coming up short in last summer's EU stress test, in which it performed worst among 51 banks tested. The government's fund is supposed to help ease troubles also at two Veneto banks, where small investors took losses of more than 11 billion euros, as well as four small banks in central Italy.