Deletes erroneous reference to April 2 in second paragraph.
By David Morgan
WASHINGTON (Reuters) - President Barack Obama is expected to decide within days how many extra U.S. troops to send to Afghanistan, the U.S. defence chief said on Tuesday.
Defence Secretary Robert Gates also suggested the initial deployment could be as small as one combat brigade, as the Obama administration moves to complete its review of Afghan strategy before NATO holds its next summit in April.
"The president will have several options in front of him and I think he will make those decisions probably in the course of the next few days," Gates told reporters at a Pentagon briefing.
Up to now, Obama had been widely expected to announce the deployment of three combat units encompassing up to 17,000 U.S. forces as part of a plan to nearly double the U.S. military presence to about 60,000 troops over the next 12 to 18 months.
U.S. military planners have considered sending two Army combat brigades, each with about 3,500 soldiers, and a larger Marine task force that could number close to 10,000 troops.
But Pentagon officials have sounded a more cautious note in recent days, amid signs that the Obama White House would devote more time to deliberation over the new president's first major deployment of U.S. forces overseas.
"It seems to me a thoughtful and deliberative approach to that decision is entirely appropriate," Gates said.
There are currently 37,000 U.S. forces in the country as part of a western military presence of about 70,000 troops.
Extra troops are needed to reverse an intensifying Afghan insurgency, particularly in the South where commanders say Western troops are in a stalemate against the Taliban.
The need for extra troops is likely to grow with the approach of the spring fighting season in April and May. A combat brigade with no experience in Afghanistan would need up to three months of training before deployment, Pentagon officials said.
"There is a realization that some decisions have to be made before the strategic review is completed," Gates said. "If only because if he does decide to send at least an additional brigade combat team -- even just one -- the next one to go would need to be notified pretty quickly."
U.S. ability to build up its military presence in Afghanistan depends heavily on the withdrawal of U.S. forces from Iraq, where 146,000 U.S. troops remain on duty.
Gates said the Obama administration has not yet begun to review alternative plans for Iraq that officials say include 23-month, 19-month and 16-month timeline options for drawing down forces.
"I expect that review to take place fairly soon," Gates said. "The situation on the ground in Iraq allows us to make the next series of decisions with respect to Afghanistan with greater flexibility."
Gates declined to rule out increases beyond the 60,000-troop mark but warned that too large a Western military presence in Afghanistan could backfire on U.S. interests.
"There is no cap," he said. "I would be deeply sceptical about further troop deployments beyond that."
On Monday, Navy Admiral Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, said he did not foresee the U.S. troop increase going beyond the extra forces requested by U.S. Army General David McKiernan, the NATO commander in Afghanistan.
"Time is moving on and so in terms of being able to respond to the needs that we have on the ground, I'm hopeful that we can get them there as soon as absolutely possible," Mullen said on Tuesday during a visit to Ottawa, Canada.
"Sooner the better," he added.
(Additional reporting by Andrew Gray in Ottawa; Editing by Bill Trott)
