WASHINGTON (Reuters) - President Barack Obama was set to unveil on Wednesday his plan to start bringing U.S. troops home from Afghanistan in a significant first step towards ending a decade-long war that is increasingly unpopular in the United States.
Obama will announce in a televised address at 8 p.m. EDT (midnight GMT) a plan to pull out 10,000 troops from Afghanistan by year's end, followed by about 23,000 more by the end of next summer, congressional aides told Reuters.
News that Obama will pull the entire 'surge' force he sent to Afghanistan in 2010 caps weeks of speculation about the future of U.S. involvement there and could increase friction between Obama and military advisors who have warned about the perils of a hasty drawdown.
Nearly 10 years after the September 11 attacks that triggered the war, U.S. and NATO forces have been unable to deal a decisive blow to the insurgent Taliban. The Afghan government remains weak and notoriously corrupt and billions of dollars in foreign aid efforts have yielded meagre results.
Obama's announcement comes the week after General David Petraeus, the outgoing commander of U.S. and NATO troops in Afghanistan, presented several options for drawing down some of the 100,000 U.S. soldiers there starting in July.
The president's decision appears to reflect the competing pressures he faces as he seeks to rein in government spending and halt American casualties without endangering the gains his commanders say they have made across southern Afghanistan.
The decision to withdraw the 33,000 troops by the end of the summer of 2012 is unlikely to sit well with the Pentagon's top brass. They worry that insurgents could regain lost territory and that fighting along Afghanistan's eastern border with Pakistan will intensify.
Outgoing Defense Secretary Robert Gates has said removing too many troops before the United States can prove it has turned a corner would be "premature.
Jeffrey Dressler, a military analyst at the Institute for the Study of War in Washington, said the Pentagon would have favoured a much smaller initial withdrawal.
"But the fact is that the conditions on the ground don't merit any sort of withdrawal -- it's not time to be pulling out a substantive amount of troops," he said. "There's a lot that has to be done in the east and you're not out of the woods in the south yet."
Yet Obama also faces mounting demands from some quarters of the U.S. Congress, impatient with a war that now costs more than $110 billion (65.5 billion pounds) a year, for a larger initial drawdown.
Even after the withdrawal of the 33,00 U.S. troops, about 70,000 will remain in Afghanistan by the autumn of 2012, more than were there when Obama took office.
The debate in Washington has shifted palpably since U.S. special forces killed Osama bin Laden in Pakistan last month.
The al Qaeda leader's death has given critics from both parties ammunition to argue that the Obama administration must narrow U.S. goals in desperately poor Afghanistan.
While the United States has embraced efforts to find a political settlement with the Taliban, officials acknowledge a peace deal may be far in the future even if one could be had.
Obama is mindful of the American public's lack of support for the war as he looks to his 2012 re-election campaign.
A Pew Research poll released on Tuesday found a record 56 percent of Americans favour bringing U.S. forces in Afghanistan home as quickly as possible.
Still, the situation on the ground in Afghanistan remains volatile and Obama will face heat from Republicans if he is seen as rushing towards the exit.
The Taliban has been pushed out of some areas of their southern heartland, but the insurgency has intensified along Afghanistan's border with Pakistan.
July marks the official start of NATO's handover to local security forces in keeping with a plan to put Afghan soldiers in charge across the country by the end of 2014.
Serious doubts remain about whether Afghan forces, plagued by desertion and illiteracy, will be up to the task.
The White House decision may embolden European nations to withdraw their own troops more quickly from Afghanistan despite past Pentagon warnings.
Analysts said Washington's allies would want to follow the American lead given the squeeze on their defence budgets, the demands of the war in Libya and the unpopularity of the Afghan mission.
"I don't see how this ends in anything other than a run to the exit. I cannot think of one European country that wants to be in Afghanistan more than the Americans," said Tomas Valasek of the Centre for European Reform in London.
The drawdown from Afghanistan underscores the Obama administration's shift towards a more explicit focus on Pakistan, the nuclear-armed nation where a weak government and powerful military are viewed with suspicion in Washington.
U.S. officials see an even bigger threat emanating from Pakistan, which was home to bin Laden and is still a major base for militants targeting Americans.
Still, analysts have cautioned that if the United States walks away from Afghanistan, it does so at its own peril because of the risk the country could topple back into the grip of extremism or renewed civil war. Both of these scenarios could again open the door to al Qaeda.
"What will be important is what happens in two or three years from now," Valasek said. "If Obama gets re-elected, and it all goes wrong, and Kabul has turned into another Mogadishu -- then he would clearly have some explaining to do."
Additional reporting by Susan Cornwell, Laura Macinnis, Phil Stewart and Alister Bull in Washington and David Brunnstrom in Brussels. Editing by Christopher Wilson