Obama to confirm Afghan troop surge
US President Barack Obama is expected to announce a troop surge of around 30,000 soldiers in a bid to overrun the Taliban in Afghanistan.
The move was described by UK Foreign Secretary David Miliband as "very significant".
The total number of American soldiers in the region is now expected to top 100,000 by next summer.
In a speech described as one of his most important since coming to power, Mr Obama is also likely to lay out plans for the further training of an Afghan security force.
White House spokesman Robert Gibbs suggested the creation of a larger homegrown national army would mark part of the exit strategy for the US.
He told ABC News: "We want to - as quickly as possible - transition the security of the Afghan people over to those national security forces in Afghanistan. This can't be nation-building. It can't be an open-ended forever commitment."
The announcement will come more than three months after the White House received a report from General Stanley McChrystal, the top US commander in Afghanistan, which recommended around 40,000 extra soldiers were needed. But senior sources in the administration have said Mr Obama will go with fewer troops.
They will be deployed on an accelerated schedule, with some in place by Christmas, it has been suggested.
In the 24-hours leading up to the announcement the US head of state phoned other Nato leaders, including Gordon Brown, outlining his plans.
The prime minister on Monday announced the UK's military commitment will be increased to more than 10,000.
