KABUL (Reuters) - Poor security in the east and south and a failure to capitalise on gains made after a 2004 poll will make it more difficult for Afghanistan to stage a meaningful presidential election on Aug. 20, a leading think tank has said. Afghanistans Taliban-led insurgency, which the US military says has hit its most violent level since the extremists groups ousting in 2001, increases the chance of fraud in the nations second presidential poll, the International Crisis Group said. Security conditions may make it difficult for people in areas of the south and east to exercise their franchise and could also provide the cover for mass fraud, the Brussels-based group said in a statement released overnight. The election is seen as a crucial point for both Kabuls Western-backed government and for Washington, which has identified Afghanistan as its top military priority and has already almost doubled the number of its troops from the 32,000 in the country in late 2008. Many of those extra troops will provide security for the poll as well as battling a resurgent Taliban, whose insurgency has spread out of traditional strongholds in the south and east. US National Security Adviser Jim Jones said after two days of meetings with Hamid Karzai and other political and military leaders in Afghanistan that Washington supported secure, credible and legitimate elections. The United States neither supports nor opposes any legitimate candidates and we are concentrating our efforts on helping to create a level playing field for all your candidates, Jones said in a statement released by the US embassy in Kabul. The ICG report examined the presidential election, where 40 other candidates are challenging Karzai, and National Assembly and district polls in 2010. Seen as weak at home and in some Western capitals earlier this year, Karzai has managed to consolidate his position in recent weeks by winning the support of some of his key former rivals and dividing the rest of the opposition. The ICG report noted that the opportunities for fraud were greater in areas where the insurgency is centred because the same regions are dominated by Pashtuns, Afghanistans largest ethnic grouping of which Karzai is a member. Participation is likely to be uneven with a drop in candidates in areas of the insurgency-hit south in particular, a stark reminder of the effect of violence, the report said. The continued low quality of police makes providing security for elections challenging. Striking flaws in the voter registry could also lay the groundwork for fraud, the ICG said. Weak state institutions and a fractured political scene will likely have a dramatic effect. The years since the last poll saw the Afghan government and international community fail to embed a robust electoral framework and drive democratisation at all levels, it said. A highly centralised system of political patronage in which the head of state wields enormous powers also brought personalities rather than policies to the fore. Most of more than $230 million the Afghan election will cost is being provided by Washington and its allies, but those resources and attention must be channelled into strengthening political and electoral institutions, the ICG said. Without due attention, the presidential and provincial polls risked being a mere collection of separate events rather than a coordinated effort towards nation building, it said. Jones also visited Pakistan and India in a trip focused on implementing President Barack Obamas new regional strategy, White House National Security Council spokesman Mike Hammer said. Obama has put Afghanistan and Pakistan at the centre of his foreign policy agenda with the new strategy aimed at defeating al Qaeda and stabilising Afghanistan.