Many American soldiers were still schoolchildren on 9/11, but the attacks drew them to the frontlines of a US adventure in Afghanistan that even after a decade has no certain outcome.

The long war has cost hundreds of billions of dollars, killed thousands and could end with more civil conflict or even the Taliban back in power, analysts say.

But for many waging the fight, the fateful events of 10 years ago remain a powerful motivation.

"To be honest, I didn't know what the World Trade Center was, but I knew it was an attack against America," 23-year-old US army 2nd lieutenant Holly Kellmurray told AFP.

She was 13 years old and in a school home economics class in upstate New York when news of the strikes on the Twin Towers broke, eventually leading her to train as an army officer and deploy to Afghanistan.

"I had no interest in the military really until 9/11. I just got struck by the patriotism -- it's just like a switch turned on and I said, 'I need to serve my country.'"

Last month was the deadliest for US troops in the course of the decade of fighting that began with the US-led Operation Enduring Freedom and snowballed into a huge effort currently involving around 140,000 troops from 48 countries.

Launched a month after the 9/11 attacks, the US-led military campaign under president George W. Bush was designed to topple the Taliban and ensure Al-Qaeda could no longer use Afghanistan as a safe haven.

Experts believe Al-Qaeda leader and 9/11 mastermind Osama bin Laden escaped over the border to Pakistan in December 2001 -- he was finally killed in a covert raid by US commandos in Pakistan in May.

So far, the war has cost America alone $444 billion and more than 1,750 dead. According to Brown University in the US, some 33,877 people -- including foreign and Afghan troops, civilians and insurgents -- have died.

But for soldiers like Captain Olaseni Bello, 30, who moved to America aged nine from Nigeria, the events of 10 years ago still fire the sentiment he felt for his adopted country's way of life when it came under attack.

"You have these two skyscrapers that pretty much mark the city -- it's a symbol, it's more than New York, it's also American entrepreneurism, international aspects, the appeal of our reach," said the army lawyer.

Sergeant First Class Celia Torres was working as a military recruiter near New York at the time of the attacks, and the 42-year-old won awards for the number of people she signed up to serve in Afghanistan.

"It's hard to say the word 'revenge'. You try not to use those words -- payback, revenge -- but that's pretty much how people felt. They just wanted to hit back," she said.

But despite the patriotic fervour, America's war faces a deeply uncertain outcome, three years ahead of a drawdown of all foreign combat forces and as a weak Afghan state struggles with corruption and fledgling security forces.

Of 100,000 US troops in Afghanistan, 33,000 will leave by mid-2012, even as a still-potent Taliban insurgency is focused on headline-grabbing suicide attacks against government officials and foreign targets.

And this year is on track to be the bloodiest yet for civilians, with casualties up 15 percent in the first six months, according to UN figures. Eighty percent of the deaths were down to insurgents.

"I'm deeply worried about what happens in 2014," said Kate Clark of Kabul-based think-tank the Afghanistan Analysts Network.

"The fear that many people have here is that if the politics aren't dealt with, what we will see is, when the international forces pull out, there will be a proper civil war."

In 10 years of conflict, battlefield successes have ebbed and flowed for the US-led troops who invaded the country on October 7, 2001 alongside the anti-Taliban mujahedeen, driving the Taliban from Kabul by early December.

Senior officers now admit that early wins in Afghanistan may have fostered a complacency that helped the Taliban rebuild later on.

A shift in focus and resources to fight the US war in Iraq led to greater instability in Afghanistan, and violence flared again in 2007 and 2008 as the Taliban regrouped in tribal areas of Pakistan close to the porous border. In 2002, 70 foreign troops were killed, but by 2008 the year's death toll was 296, rising to 521 in 2009, according to independent website iCasualties.org.

After US President Barack Obama took office in 2009, he promised to end the conflict by sending 30,000 troops to Afghanistan's south, the insurgency's heartland, to hammer the Taliban.

But now as some foreign troops start to withdraw, the Kabul government and its Western sponsors are trying to pursue peace talks with the Taliban, raising the possibility of their return to power -- a prospect bound to make many serving soldiers uneasy.

A memorial ceremony will be held on Sunday's anniversary of 9/11 at Bagram Airfield, the US military's main command center for eastern Afghanistan.

Outside the main operational hub on the giant base sits a large slab of steel from the World Trade Center, adorned with a small, frayed American flag -- a potent reminder of the sacrifices wrought by the events a decade ago.

Related Links
The Long War - Doctrine and Application

Tweet