US President Barack Obama has delivered a speech spelling out his review of Afghan strategy and has ordered a surge of 30,000 additional US soldiers. Mr Obama also set out how the US would approach its exit strategy and urged allies to send more troops. The new deployment over six months will bring America's troop strength in the country to more than 100,000, in the fight against Taliban militants. Mr Obama believes the surge will help prepare the handover to Afghan forces. Mr Obama reached his deployment decision after more than three months of deliberations and 10 top-level meetings with advisers. Gen Stanley McChrystal, the US commander in Afghanistan, welcomed the speech, saying he had been given "a clear military mission" and the necessary resources. Some 32,000 other foreign troops are serving in Afghanistan but Nato allies have been cautious about contributing further forces. The White House wants to convey that this is Barack Obama's war and he is clear about the aims he wants to achieve, the BBC's Matthew Price reports from West Point. Taliban threat Mr Obama delivered his nationally televised speech to cadets at the West Point military academy in New York. Stressing that the US was in Afghanistan because of the 9/11 attacks on America by al-Qaeda militants, he said that their Taliban allies had "begun to take control over swaths of Afghanistan" while committing "devastating acts of terrorism" against Pakistan. US forces, he said, lacked "the full support they need to effectively train and partner with Afghan security forces and better secure the population". "I have determined that it is in our vital national interest to send an additional 30,000 US troops to Afghanistan," he told the cadets. "After 18 months, our troops will begin to come home." Mr Obama said he was aware of the gravity of his decision to send the extra troops but he urged Americans not to see the conflict as a new Vietnam War. America was backed by a "broad coalition of 43 nations", he said, and was not facing a "broad-based popular insurgency". "Most importantly, unlike Vietnam, the American people were viciously attacked from Afghanistan, and remain a target for those same extremists who are plotting along its border," the US leader added. Calling on America's allies to boost their troop commitment, Mr Obama said: "What's at stake is the security of our allies, and the common security of the world." The US would take the Iraq experience as its model for withdrawal, he added. "Just as we have done in Iraq, we will execute this transition responsibly, taking into account conditions on the ground," he said. Pledging to continue to advise and assist Afghanistan's security forces, he warned: "It will be clear to the Afghan government - and, more importantly, to the Afghan people - that they will ultimately be responsible for their own country." "The days of providing a blank cheque are over," he added. Other priorities Mr Obama outlined included enhancing US domestic security, preventing nuclear materials falling into the hands of terrorists and forging better ties with the Muslim world. Domestic unease Earlier, the US president outlined his new strategy to Afghan counterpart Hamid Karzai in an hour-long video conference. He told Mr Karzai that US efforts in Afghanistan were not "open-ended" and would be measured against goals over a two-year period, the White House said. Rising violence - more than 900 US soldiers have died in Afghanistan - and August's discredited elections have fanned mounting domestic opposition to the eight-year-old war. Nato officials said on Tuesday that President Obama had asked European allies to contribute between 5,000 and 10,000 new troops to Afghanistan. But France ruled out deploying more combat soldiers, though it might send military trainers, while Germany said it would wait until after a 28 January conference in London on Afghanistan before deciding on any troop increases. On Monday, Britain confirmed it was sending 500 more troops, taking the UK's total deployment to 10,000. Italy has also said it will increase its force, although without saying by how much. Source: BBC