In southern Afghanistan, U.S. Army troops have officially replaced several hundred Marines who had been based at Kandahar Airport, which was captured from the Taleban more than a month ago. But even though most of the Marines are returning to their ships for a journey back to the United States, one young Marine is staying behind.

At first glance, 26-year-old Lance Corporal Ajmal Achekzai fits the image of an American marine. Tall and broad-shouldered, he stands rigidly at attention until he is told to relax. He then breaks into an easy smile and chats with an accent that clearly emphasizes his upbringing in California in the western United States.

But when he mingles with local workers at the airport, Mr. Achekzai reveals his true heritage: a proud Afghan who has never forgotten his homeland. "This is where I was born. I was born in Kabul, but this is where my roots started in Kandahar," he said. "So it is a great experience for me. I knew I was coming back. I never thought that I was going to be a Marine coming back to Afghanistan."

Both of Mr. Achekzai's parents are ethnic Pashtun. His mother was born in Kandahar; his father in Kabul. The Marine still speaks the two main languages of Afghanistan, Dari and Pashto, fluently, even though he left Afghanistan when he was just five years old.

Mr. Achekzai says he remembers the day his family fled to the United States in 1980. He recalls seeing columns of tanks of the invading Soviet Army rumbling through the streets near his house in Kabul.

His father, who was a politics professor at Kabul University, had no choice but to move the family. The Russians suspected him of being a supporter of the Mujahedin rebels and were about to arrest him.

The Achekzai family settled in northern California, where Ajmal and his younger brother grew up in two very different worlds. At home they were strict Afghan Muslims. At school, they were just like any other American boys, who loved to play baseball and eat pizza.

Even though he is not yet a U.S. citizen, Mr. Achekzai says he joined the U.S. Marine Corps because he wanted to serve the country that gave his family not only the chance to survive, but to succeed.

When the United States took its war against terrorism to Afghanistan in early October, he was one of the first marines to volunteer for duty inside Afghanistan. "I wanted them to send me," he said. "I was emailing me gunny [commander] everyday. 'Are you going to send me? Do you need me or not?'

He says he did not volunteer just because he wanted to see his homeland again. He felt that in his role as an interpreter, he could help many American soldiers see the good side of Afghanistan and the positive aspects of Islam. "It gives me a chance to educate them. That not every Afghan is like this; that not every Muslim is like that," he said.

Mr. Achekzai says he also felt it was his duty to convince his fellow Afghans that the United States did not simply want to bomb the country and leave. "I tell them that we are here only to protect. We are not here to ruin the country. We want the Afghans to run the country and develop it," he said. "We are here to help."

The messages appear to be getting across to people on both sides. There have been no reports of tension between U.S. soldiers and local people in Kandahar.

In the city, Mr. Achekzai has become somewhat of a celebrity. Whenever he goes into town to speak to the locals, hundreds of people gather to stare and smile at the American soldier who is one of them. Ghani Abdul says he still can not believe there is an Afghan serving in the U.S. military.

It is amazing and shocking, Mr. Abdul says. He is very happy to see that the U.S. forces have an Afghan in their ranks. Mr. Abdul says the Marine has done much to persuade the people here that Afghan and Americans could become long-term friends.