In his first major military move, United States President Barack Obama Tuesday approved the deployment of 17,000 more troops to Afghanistan, saying they were needed "to stabilize a deteriorating situation."
"There is no more solemn duty as president than the decision to deploy our armed forces into harm's way," Obama said in a statement.
"I do it today mindful that the situation in Afghanistan and Pakistan demands urgent attention and swift action."
Obama said the deployment orders were in response to a months-old request by the U.S. commander in Afghanistan, General David McKiernan, who had asked for 30,000 more troops.
The White House said some 17,000 troops will be deployed to Afghanistan ahead of the Afghan elections scheduled for Aug. 20, significantly building up the 38,000 U.S. force already on the ground battling a growing insurgency.
New page with Karzai
The announcement comes as the White House continued its broad review of U.S. policy on Afghanistan.
Obama spoke to Afghan President Hamid Karzai overnight for the first time since the U.S. president took office nearly a month ago.
Ties between Kabul and Washington have been strained since Obama's inauguration, with the new administration questioning Karzai's ability to govern effectively and the Afghan president hitting back at the killing of civilians by foreign troops.
But after a telephone conversation overnight, Karzai's spokesman said: "We have opened a new page."
"Mr. Obama spoke with the president about various issues including steps for improving security in the region, equipment and training of the national army, further strengthening of bilateral relations, and the increase of forces was also discussed," said presidential spokesman Humayun Hamidzada.
Plan to expand U.S. troops
The forces are part of an anticipated build-up that could expand the U.S. military presence in Afghanistan to 60,000 troops.
The new forces will include a Marine expeditionary brigade of some 8,000 troops and an Army brigade of 4,000 soldiers equipped with Stryker armored vehicles, the Pentagon said.
"The decision was communicated to the Pentagon yesterday. The orders were signed today," White House spokesman Robert Gibbs told reporters.
As well as American forces, there are also some 30,000 troops from NATO nations attempting to stabilize Afghanistan and struggle to hold territory against an increasingly bold Taliban insurgency.
U.S. officials say Taliban safe havens over the border in Pakistan are a major asset for insurgents.
Obama indicated that the units being sent to Afghanistan had initially been earmarked for Iraq, saying the drawdown of U.S. forces there "allows us the flexibility to increase our presence in Afghanistan."
Obama has pledged to pull out all U.S. combat troops from Iraq within 16 months, but commanders are pushing for a slower withdrawal, warning that security gains are fragile.