By Andrew Quinn and Phil Stewart
WASHINGTON (Reuters) - The first of 30,000 new U.S. troops will arrive in Afghanistan in two to three weeks, top U.S. officials said on Wednesday, even as they made clear plans to start bringing the soldiers home in 18 months could slip.
President Barack Obama on Tuesday announced the major increase in U.S. forces fighting the Taliban, bringing the U.S. troop presence there to almost 100,000 in a buildup officials hope will secure Afghanistan and allow U.S. soldiers to start pulling out by the summer of 2011.
Defence Secretary Robert Gates, leading off testimony by top Obama officials at the Senate Armed Services Committee, said the first new U.S. forces would be sent in 2-3 weeks, starting an 18-24 month "extended surge."
Gates said the aim was to shift responsibility for security to the Afghans themselves. "Beginning to transfer security responsibility to the Afghans in summer 2011 is critical - and, in my view achievable," he said.
But in a sign that U.S. commanders were keeping options open on the timing of a troop drawdown, Gates said they would review progress in December 2010 and final decisions on when to begin the withdrawal would depend on that assessment.
He said Washington would not abandon Afghanistan to its fate if the security situation appeared untenable. "We're not just going to throw these guys into the swimming pool and walk away," he said.
Obama, in his high-stakes address, depicted the Afghan campaign as vital to U.S. security and said it was aimed at defeating the Taliban and preventing further attacks by al Qaeda, which was behind the September 11, 2001 attacks.
The top Republican on the Senate committee, John McCain, voiced doubt about the withdrawal plan, echoing fears that it could allow Taliban militants to wait out the U.S. troop surge and reassert themselves later.
"A date for withdrawal sends exactly the wrong message to both our friends and our enemies," said McCain, Obama's defeated Republican rival in the 2008 presidential election.
OBAMA'S WAR
Obama's speech set him up as the architect of a new phase of the eight-year old Afghan war, adding $30 billion in costs in the coming year as the country struggles with record federal deficits, high joblessness and the on-going economic bailout.
Many of Obama's fellow Democrats have voiced doubt about escalating the costly conflict, while Republicans have complained that the drawdown date ties the military's hands.
The debate carries clear risks for Democrats ahead of mid-term elections next year in which Republicans hope to take chunks out of Democratic majorities in both chambers of Congress. Obama himself faces re-election in 2012.
Admiral Mike Mullen, chairman of the military Joint Chiefs of Staff, told the committee 20,000 to 25,000 more troops would be in Afghanistan by the height of the summer fighting season in July and final deployments could take place as late as the fall.
But plans to pull them out -- which could prove politically crucial -- were less clear.
Under questioning by Republicans, Gates and other top officials suggested the 18-month timeline on withdrawals could change if circumstances show the fight is not being won.
"I do not believe we have locked ourselves into leaving," Secretary of State Hillary Clinton told the committee, calling Obama's withdrawal target "a signal" that the United States did not foresee an indefinite occupation.
PAKISTAN, AFGHANISTAN UNDER PRESSURE
Clinton said Pakistan -- Afghanistan's fragile, nuclear-armed neighbour -- would be pressed to more actively pursue militants in its own territory and promised that Washington would press Afghan President Hamid Karzai to fulfil promises to fight corruption.
Karzai's office issued a statement that said Afghanistan welcomed Obama's change in strategy, although unusually it did not provide a comment from Karzai himself, often depicted as a weak link in Obama's Afghan strategy.
The top U.S. and NATO commander General Stanley McChrystal, who had said he needed as many as 40,000 troops to win the war, welcomed Obama's promise to boost forces.
But the Taliban, in a statement issued by email, said the increase would only bolster their resolve. "This strategy by the enemy will not benefit them," it said.
European leaders were quick to voice support for the new U.S. plan, but most delayed committing new troops to an uncertain, unpopular and deadly military campaign. U.S. officials have said Washington in seeking 5,000-7,000 more troops from allies.
Britain promised to send 500 extra soldiers, boosting its contingent to about 10,000. Poland said it would send 600 more to join its 2,000-strong force while Italy promised an unspecified number. Others kept it vague.
NATO Secretary-General Anders Fogh Rasmussen, speaking in Brussels, said it was realistic to expect Afghans to take over security work in 10 to 15 areas and districts next year but the transition could only happen if conditions were met.
(Additional reporting by Adam Entous, David Morgan and Sue Pleming in Washington; David Brunnstrom in Brussels, Sayed Salahuddin in Kabul and Zeeshan Haider, Augustine Anthony and Michael Georgy in Islamabad; Editing by David Storey)
