KABUL (AFP) - The United States warned Friday that delays in resolving troubled Afghan polls would benefit the Taliban as a vote commission warned up to half a million ballots could be investigated for fraud. Britain, which behind the United States is the second biggest contributor of foreign troops fighting in Afghanistan, refused to be party to any whitewash as mounting allegations of vote-rigging and fraud overshadowed the polls. Afghans voted on August 20 in only their second direct presidential election, marred by low turnout blamed on intimidation and record levels of violence eight years after the US-led invasion ousted the Taliban regime. Richard Holbrooke, the US pointman for Afghanistan and Pakistan, was asked by the BBC whether it could create an unstable environment if counting from the presidential election took months as some have predicted. I dont think youre going to have a process thats drawn out that long, at least I hope not, Holbrooke told the BBC in an interview. The beneficiary of that would be the Taliban and Al-Qaeda, and I need to underscore that... the beneficiary of any delays of the sort youre talking about would be the Taliban and Al-Qaeda, and everybody understands that. Up to half a million ballots cast in Afghanistans fraud-tarnished polls could be quarantined and investigated over alleged irregularities, an election commission spokesman said Friday. IEC spokesman Noor Mohammad Noor, IEC spokesman, said 447 polling stations, or 0.2m ballot papers, had already been quarantined. It will go up to 660 polling stations. Maybe it will go up to 0.5m ballot papers, he told AFP. Preliminary results are due on Saturday, with the international community urging officials to ensure a clean process that gives legitimacy to the victor and brings an end to the political uncertainty. David Miliband said he had concerns about serious allegations of fraud. We will not be party to any whitewash when it comes to the elections, Miliband told the BBC. Thats why the United Nations established the electoral complaints commission, its why theyve dismissed the results from 83 polling stations, so of course we have concerns about very serious allegations of fraud. Official results are due after Sept 17, but int'l observers have urged that no winner be declared until the fraud claims are resolved. Holbrooke said scrapping the election was out of the question. A leading think-tank expressed concern about the dangers of a power vacuum should the election be unresolved for months. London-based policy research group, the International Council on Security and Development (ICOS) released a map showing that a resurgent Taliban now has a significant presence across virtually all Afghanistan. It warned that any potential run-off could be delayed until spring because of harsh winter conditions, leaving Afghanistan in a constitutional vacuum. This raises the possibility of both a lack of legal authority in the presidency and resulting political instability and government paralysis dragging on for many months, said ICOS president Norine MacDonald. ICOS said the Taliban had widened its nationwide reach since last year and now had a permanent presence in 80 percent of the country with its influence spreading in once relatively peaceful regions in the west and the north. Meanwhile, Prince Edward spent 24 hours visiting British troops on the front line in Afghanistan, Buckingham Palace said Thursday. Queen Elizabeth IIs youngest child arrived in the troubled southern Helmand Province late Tuesday and left on Wednesday, a palace spokesman said. Edward, 45, is the royal colonel of 2nd Battalion, The Rifles and spent the day with soldiers from the unit in the town of Sangin, where they have spent the past five months seeking to bring greater security. The soldiers have been at the forefront of the fight against insurgents in Helmand who have sought to destabilise the area, said a Ministry of Defence (MoD) spokesman.