The oath of office was administered by Vice President Joe Biden. Lew's family members were also in attendance, Treasury said in a statement.

　　Lew was confirmed on Wednesday by the U.S. Senate as the new Treasury Secretary, as Democrats and Republicans are haggling over the looming government spending cuts. Obama last month nominated the former White House Chief of Staff to lead the Treasury Department, a big step in shaping his economic team for the second term.

　　Lew, a budget expert, served as director of the White House Office of Management and Budget (OMB) in President Bill Clinton's cabinet from 1998 to 2001. During his tenure at the OMB, he helped the federal government achieve budget surpluses for three consecutive years.

　　Lew's imminent challenges as the Treasury chief would be achieving consensus with GOP leaders to reduce the mounting government debt and coping with the negative effects of the looming government spending cuts.

　　Automatic spending cuts of roughly 85 billion U.S. dollars are set to hit various government departments this year starting March 1, as agreed by Democrats and Republicans in January in their negotiations to resolve the so-called "fiscal cliff."