WASHINGTON (AFP) - As fresh US troop reinforcements prepare to deploy to Afghanistan, veterans of the war Thursday decried past mistakes and warned the conflict cannot be solved by military means alone. By the time I left Afghanistan, I felt that the US being there was a big mistake, retired US Marines corporal Rick Reyes told the Senate Foreign Affairs Committee. I feel strongly that military intervention is not the answer. His comments echoed congressional testimony given by Committee Chairman John Kerry as a Vietnam War veteran in 1971, when he had famously asked: How do you ask a man to be the last man to die for a mistake? Now as then, veterans voiced their reservations about the already costly and protracted conflict in Afghanistan, although they argued against a rapid withdrawal of troops. If we leave without providing the security, propping up the government, propping the local villages and the people that are there, giving them some sense of structure, some sense of stability and security, we will be back, said Genevieve Chase, a retired US Army Reserve sergeant. Reyes blasted US President Barack Obamas decision to deploy 21,000 additional troops to Afghanistan as a big mistake. Some 40,000 US troops are already in the country with about 32,000 other foreign allied forces deployed under Nato authority. At a minimum, this occupation needs to be rethought, Reyes said. But three other Afghanistan veterans argued for more US commitment to the conflict. We are underfunded and undermanned in Afghanistan, retired US Army captain Westley Moore told the Senate panel. But he also stressed the importance of more non-military aspects of the US strategy. If we increase security aspects ... then we can actually start allocating more resources to make not only Afghanistan not a safe haven for Al-Qaeda, but also provide the security and safety and the future for the Afghan people, he said. Former army staff sergeant Christopher McGurk recalled the dying moments of 19-year-old Evan ONeilln, who apologised for not completing the mission after being shot near the Pakistani border. My own anger and sense of betrayal comes from the possibility that we may not come to a resolution in Afghanistan and that the blood that has been shed by the victims of 9/11, the Afghan people and men like ONeill would be in vain, McGurk said. Republican lawmakers expressed scepticism about Obamas strategy for Afghanistan, which focuses on rooting out Al-Qaeda, boosts civilian efforts to rebuild the impoverished country and places nuclear-armed Pakistan at the centre of the fight. I have no idea what it is, other than sending additional troops, said Republican Senator Bob Corker. I hope we dig a lot deeper. Some Democrats also showed concern about the plan. The escalation may further destabilise the situation in Afghanistan to the detriment of US security, said Senator Russ Feingold. We may be sending our troops in the eye of the storm without addressing the greatest threat to our security, which lies on the Pakistani side of the border. Kerry acknowledged that there is much still to be done in Afghanistan and Pakistan. Kerry drew an analogy between the war in Afghanistan and the Vietnam War. Once again, we are fighting an insurgency in a rural country with a weak central government. Our enemy blends in with the local population and easily crosses a long border to find sanctuary in a neighbouring country, said Kerry. We ignore these similarities at our peril.