The US Department of Justice has upped the stakes in its battle with Swiss bank UBS over the violation of tax laws. Overnight, the US government has demanded more names of US citizens who are believed to have used secret Swiss bank accounts to be disclosed to the Internal Revenue Service. A statement issued by the DoJ said it believes 'as many as 52,000 U.S customers hid their UBS accounts from the government,' which is over twice as many as the 20,000 previously identified. According to court documents, the government alleges that UBS trained its bankers to avoid detection by U.S. authorities. John DiCicco, acting assistant attorney general for the Justice Department's tax division, said in a statement: 'At a time when millions of Americans are losing their jobs, their homes and their health care, it is appalling that more than 50,000 of the wealthiest among us have actively sought to evade their civic and legal duty to pay taxes.' 'It is time for those who are trying to hide from the IRS to rethink their actions,' he added.