Q+A: Understanding Obama's Afghan strategy

WASHINGTON (Reuters) - New details are emerging about U.S. President Barack Obama's plan to increase the size of the force in Afghanistan, including on the number troops, the timetable for withdrawal and contribution of NATO allies.

Here are some questions and answers about troop deployments to Afghanistan in an escalation of a war that began in 2001.

HOW MANY TROOPS ARE GOING?

Obama announced 30,000 more troops for Afghanistan. Subsequent testimony in Congress revealed that this figure could rise to 33,000 without any additional authorization if Defense Secretary Robert Gates decides more "enablers" are necessary to help protect U.S. forces. These include specialists who perform tasks such as destroying landmines, treating the injured and gathering intelligence. Gates told Congress he hoped the additions would not become necessary. There are 68,000 U.S. troops in Afghanistan now.

WHEN WILL THEY ARRIVE?

Administration officials initially said the 30,000 additional troops would arrive within six months, taking Pentagon war planners by surprise. Obama hedged slightly, saying they would deploy in the first part of 2010.

Subsequently, Admiral Mike Mullen, chairman of the U.S. military's Joint Chiefs of Staff, said they may not all be in place until next fall.

The first part of a 9,000-member Marine Corps brigade is due to arrive in Afghanistan in the next two to three weeks. Mullen told Congress he expected that a total of 20,000 to 25,000 additional troops would arrive in Afghanistan by July.

WHAT'S THE DEADLINE FOR WITHDRAWAL?

Obama said troops would start to withdraw from Afghanistan in July 2011. Gates and U.S. Secretary of State Hillary Clinton told Congress this date could change depending on conditions on the ground. There will be another review of the war effort in December 2010 and the target could be revised at that time, they said.

While some troops may be pulled out of Afghanistan in July 2011, it is not clear how substantial or frequent subsequent troop drawdowns would be. Officials suggest a future withdrawal would be very gradual and said there is no deadline to remove all troops from the country.

HOW MANY TROOPS IS NATO CONTRIBUTING?

NATO Secretary-General Anders Fogh Rasmussen said NATO allies promised to send around 7,000 more troops to Afghanistan. But it is not clear whether this will boost the overall NATO number in a meaningful way in the next two years.

The Netherlands and Canada plan to withdraw combat forces of 2,100 and 2,800 in 2010 and 2011, respectively. U.S. officials acknowledge that some of the "new" NATO troops being pledged are already in the country, having been deployed temporarily to boost security for Afghanistan's fraud-marred August election. NATO sources peg that number at 1,500.

HOW MUCH DOES IT COST?

The Pentagon forecasts the cost of the 30,000-troop increase at $30 billion to $35 billion, higher than previous estimates. But Gates told Congress this was just "a ballpark figure." Representative David Obey, chairman of the House of Representatives Appropriations Committee, has suggested a war tax to fund the escalation, but House Speaker Nancy Pelosi said she opposes that proposal.

WHEN DO AFGHANS TAKE THE LEAD ON SECURITY?

Central to Obama's war strategy is handing over security to Afghanistan's army and police, something that Gates says will happen province by province, district by district, starting in July 2011. That's well ahead of the 2013 date previously suggested by General Stanley McChrystal, the top U.S. commander in Afghanistan.

Gates and Mullen stressed to Congress that the transition will not happen all at once and, indeed, there is no deadline or broader timetable to hand over security to the Afghans.

WHAT IS THE TRAINING TIMETABLE?

For the Afghan army, the Pentagon wants to boost the number of Afghan soldiers to 240,000 from 96,000 today. Mullen's testimony suggested a rate of growth of about 40,000 troops per year. He cited these targets:

-- 134,000 by October 1, 2010

-- 174,000 by September 30, 2011

At that rate, 240,000 would be reached in 2013.

For the Afghan police, the goal is to bring the number to 160,000 from 92,000 today. Mullen cited the following targets:

* 97,000 within one year

* About 130,000 by September 30, 2011

(Reporting by Phil Stewart; Editing by Patricia Wilson and Will Dunham)