Under pressure over the increasingly unpopular war in Afghanistan, US President Barack Obama underlined the limited nature of his "fairly modest" objectives and insisted they can be achieved.
In an interview with CBS's "Early Show" broadcast on Sunday, Obama said no one expected the US-led effort in Afghanistan to turn the country into a perfect Western-style democracy.
"What we're looking to do is difficult, very difficult, but it's a fairly modest goal, which is, don't allow terrorists to operate from this region; don't allow them to create big training camps and to plan attacks against the US homeland with impunity.
"That can be accomplished," he said. "We can stabilise Afghanistan sufficiently and we can get enough cooperation from Pakistan that we are not magnifying the threat against the homeland."
A US-led invasion of Afghanistan in late 2001 ousted the Islamic extremist Taliban regime, accused of harbouring Osama bin Laden - the chief suspect for the September 11 attacks on America that killed nearly 3,000 people - and leaders of his Al-Qaeda network.
But in almost nine years since, a Taliban insurgency against President Hamid Karzai's Western-backed government has become increasingly emboldened despite the presence now of almost 150,000 allied troops.
July was the deadliest month for US troops since the start of the war and the growing number of body bags is beginning to test the resolve of the American public.
"If I didn't think that it was important for our national security to finish the job in Afghanistan, then I would pull them all out today," Obama said. "Because I have to sign the letters to these families when a loved one is lost."
Despite the growing clamour against the war, US Defense Secretary Robert Gates insisted Sunday that large numbers of American troops would remain after a limited July 2011 drawdown announced by Obama earlier this year.