The United States must take serious and bold measures to tackle its mounting debt challenge in a timely manner, said some prominent experts on budget issues on Tuesday. If the lawmakers are \"bold and do it in a smart manner,\" the public will reward them, said Erskine Bowles, who was White House Chief of Staff under President Bill Clinton, before the U.S. Congress\' bipartisan debt reduction \"supercommittee.\" The newly-formed congressional deficit reduction panel, formally named the Joint Select Committee on Deficit Reduction, was tasked to identify at least 1.2 trillion U.S. dollars in deficit cuts by Nov. 23, a key element of the partisan debt ceiling wrangling this summer. During Tuesday\'s Congress testimony, Bowles and three other budget experts urged the panel to go trillions beyond that savings target. Senator Patty Murray of Washington, the top Democrat on the supercommittee, said the panel is entering \"the final critical phase\" of its work, adding that a failure to find ways to reduce the debt would be unacceptable. So far, the two parties remain unwilling to compromise, with Republicans reluctant to raise the tax and Democrats unhappy with Medicare cuts. Former Republican senator Alan Simpson said in his testimony that the supercommittee is facing a tremendous challenge. However, he said, the U.S. economy as well as its government credibility would be damaged if the panel does not take bold action. The experts held that the committee members, six Republicans and six Democrats, had to walk the fine line between putting the nation\'s fiscal house in order and protecting programs that keep the economy strong. The U.S. federal government registered a nearly 1.3 trillion U. S. dollars budget deficit for the 2011 fiscal year ending September, fresh evidence of the mounting budgetary pressure facing the world\'s largest economy.