By Andy Gallacher
BBC News, Washington
There are already about 34,000 US troops deployed in Afghanistan
This was US President Barack Obama's first major military decision and it was a big one.
America's new commander-in-chief approved the deployment of a further 17,000 military personnel to Afghanistan.
In a statement released by the White House, President Obama said "the situation in Afghanistan and Pakistan demands urgent attention".
Military advisers to the president have made it clear that the situation in Afghanistan is destabilising quickly.
According to a report from the United Nations, the number of civilian deaths increased by 39% in 2008.
The Obama administration is also extremely concerned about a resurgence of the Taleban - a force that was ousted back in 2001. According to some reports they now control huge areas within the country and that is something America wants desperately to change.
Throughout his presidential campaign Mr Obama made it clear he was going to shift the emphasis away from Iraq and focus more resources on Afghanistan.
The Obama administration is concerned about a Taleban resurgence
Commanders on the ground have asked for an additional 30,000 troops and there is speculation that they may just get what they want. That could see up to 60,000 troops in Afghanistan, almost doubling the number of soldiers on the ground today.
The 17,000 new additions will arrive in time for the warmer weather in Afghanistan. That, say military advisers, usually brings an increase in fighting.
The deployment will be made up of 8,000 marines, and 4,000 army soldiers, plus another 5,000 support staff.
They will serve in the south of Afghanistan, where the violence has been worst. They will also arrive ahead of the national elections in August, a crucial time for Afghanistan.
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But this is about more than just boots on the ground.
President Obama and his team are working on a new strategy for the region.
They plan to present what the White House is calling "achievable goals" and a "comprehensive strategy" for their approach to Afghanistan.
That review is due to be announced at the end of March - just before the next Nato summit.
That is no accident. The operation in Afghanistan is a multi-national one and it is clear that America cannot achieve any kind of victory alone.
President Obama says he wants to move forward "in concert with our friends and allies" - a clear indication that he could well call on Nato and its member countries to commit more of their resources to Afghanistan.
That could be another battle that the Obama administration will have to fight, but it is clear that the US, under its new commander-in-chief, will be in Afghanistan for many years to come.