BAGRAM AIRFIELD, Afghanistan — Many of the troops at this sprawling U.S. air base were in their mid-teens when they watched the planes hit the World Trade Center's twin towers on television and vowed to join the military.
Eight years later, many of those who enlisted in the wake of the Sept. 11, 2001, attacks are now part of a massive military effort in Afghanistan that some are saying has no clear exit.
Remembrances of the attacks started at dawn Friday, with more than 1,000 service members donning shorts and sneakers to run exactly 9.11 kilometers (about 5.5 miles) to commemorate the day and remember troops who have died in the fighting since.
Army Sgt. Joshua Applegate of Springfield, Mississippi, was in high school when the planes hit the towers, and enlisted two years later, though he said he had wanted to do it right away.
"I like my country too much not to," said Applegate, who arrived in Afghanistan in April and now facilitates transport and other logistics at Bagram Airfield, the main U.S. base in the country, located just north of the capital, Kabul.
It's nearly eight years since U.S. forces invaded to oust the Taliban and hunt for al-Qaida leaders, including Osama bin Laden, who remains at large. Now soldiers like Applegate are fighting a war that is shifting its focus amid waning public support.
Soldiers no longer talk about capturing bin Laden, and instead discuss helping the Afghan people and strengthening its government. The phrases are optimistic, but they also suggest a mission that is years from completion. Afghanistan's government is rife with corruption, its people largely uneducated and last month's presidential election was plagued by mounting evidence of fraud.
Many troops called Friday's anniversary a galvanizing event, and said marking the day reminds them that the U.S. mission here is important.
"It's still one of the reasons why we're here. Sept. 11 is part of it. For those of us who see the repercussions of fighting, it's still there every day," said Air Force Capt. Christopher Dupuis, 26, of Lacey, Washington.
At 5:16 p.m., the exact time in Afghanistan when the first of the two planes hit the World Trade Center in New York City, a ceremony began at Bagram with an officer reading a minute-by-minute timeline of events on that day. The base's U.S. flag fluttered at half-staff as more than 200 soldiers stood for the singing of "America the Beautiful" and the national anthem just ahead of sunset.
Navy Petty Officer 1 Casey Morgan told the crowd that she wasn't patriotic until the planes struck. Soon after, she looked at her job at a Waffle House and decided she wasn't doing enough for her country or herself, and joined up.
"My country was at war and I was serving waffles to stranded travelers," said the 25-year-old from Quantico, Virginia.
Ceremonies also were held at the U.S. Embassy in Kabul and at other U.S. military bases in Afghanistan.
The anniversary may bring back memories, but the war's mounting casualties are a reminder of how much has changed. Afghanistan is no longer an operation of targeted strikes to rout the Taliban and ferret out al-Qaida leaders. It is now an all-out effort, with more than 21,000 troops added this year by President Barack Obama and potentially more to come.
The added forces have meant more contact with the enemy. August was the deadliest month for U.S. troops so far, with 51 killed. And 2009 has been the deadliest year of the conflict for American forces. Since the invasion, at least 747 members of the U.S. military have died in Afghanistan and the region, according to figures from the Defense Department.
The U.S. and its allies invaded Afghanistan in October 2001 to oust the Taliban regime for sheltering al-Qaida leaders who planned the Sept. 11 attacks on New York and Washington.
The Taliban were quickly routed, but the militants regrouped and have mounted an increasingly strong insurgency over the past three years that threatens Afghanistan's struggling democracy.
Recent opinion polls in the U.S. suggest Americans may be tiring of a conflict that some say is unwinnable and now seems far removed from the effort to find bin Laden.
In mid-July, an AP poll indicated that 53 percent of Americans opposed the Afghanistan war and 44 percent supported it. In August, an ABC News-Washington Post poll found that 51 percent said the war was not worth fighting, while 47 percent said it was worth it.
Afghan President Hamid Karzai expressed his condolences to the families of the Sept. 11 victims.
"I hope that eight years after this devastating tragedy, the world will continue to struggle against terrorism," Karzai said in a statement.
At Bagram, troops said they worried Americans weren't making the connection between the Afghanistan war and the 2001 attacks strongly enough.
"I feel that a lot of people have forgotten. I would have them replay the video from that day," said Air Force Technical Sgt. Shawn Merchant, 33, of Ellsworth, Maine.
Merchant, who helps maintain fighter planes at Bagram, just started his second tour in Afghanistan. He says he sees some changes since 2007: Everything at Bagram is bigger and more permanent.
Meanwhile, the planes are dropping fewer bombs. Directives issued by the top U.S. commander in Afghanistan have called for more caution with air strikes. Recent strikes that have killed civilians have been used as propaganda tools by Taliban militants.
In Kabul, residents said they remembered the 2001 attacks as the moment the world started paying attention to their plight under the Taliban. Many pointed out that men can now shave their beards and girls can attend school, but at the same time the large presence of U.S. forces and increasing violence makes them wary.
"It's good the Americans are here. Roads have been built," said Sayeda Miri, 28, as she shopped for children's toys in a downtown bazaar. But she said it feels like her country is getting more dangerous.
"There are more suicide bombings and rocket attacks every month," she said.
Associated Press writer Amir Shah in Kabul contributed to this report.