UNITED NATIONS - The United Nations and the United States have increased their pressure on the Afghan government to allow a thorough review of the August 20 presidential election following mounting allegations of vote rigging, diplomats and news reports said Tuesday. The top UN official in Afghanistan Tuesday urged Afghan election officials to move forward with efforts to reach a final and just outcome for the election. And the US State Department said it could take months to sort out the many allegations of vote fraud. State Department spokesman Ian Kelly told reporters in Washington the US is not in position to say who might eventually be declared the winner or whether there should be a runoff election between the top two finishers. Kelly said the most important thing is that the allegations of fraud be addressed in a way that gives ordinary Afghans confidence that the outcome of the voting is legitimate. He said Secretary of State Hillary Rodham Clinton spoke by phone on Monday with the US ambassador in Kabul, Karl Eikenberry, but he offered no details. On Tuesday, the UN-backed Election Committee of Afghanistan reports that with 91.6 percent of the polling stations tallied, incumbent President Hamid Karzai has 54.1 percent of the vote. His closest rival, former Foreign Minister Abdullah Abdullah, is second with just 28.3 percent. The Afghan Electoral Complaints Commission on Tuesday, however, ordered a partial recount of the ballots for the presidential contest. It cited clear and convincing evidence of fraud in the elections, noting an exceptional number of votes cast in relation to the number of ballots available. The international community heaped praise on Afghanistan in the days following the Aug. 20 vote, though allegations of fraud surfaced almost immediately. Nonetheless, Kai Eide, the UN special envoy to Afghanistan, called on the IEC and EEC to redouble efforts to reach an official vote tally. All of us are keen to see the processes move forward without delay so that a final and just outcome is arrived at, he said, according to his statement read out at the regular briefing at UN Headquarters in New York. This includes excluding from the preliminary count results from ballot boxes where there is evidence of irregularities. The EEC, for its part, ordered the IEC to conduct a recount for polling stations that had a turnout greater than 100 percent and for polling stations where any one candidate received more than 95 percent of the vote. The official results were expected Sept. 17, though it is unclear if the EEC order will affect that deadline. The decision to audit and conduct a recount was made after US Ambassador to Afghanistan Eikenberry urged President Karzai on Monday to permit the investigation into vote fraud, senior State Department officials told CNN. The ECC said it received more than 2,000 complaints since the Aug. 20 election.