INDIANAPOLIS - Two days after passing his citizenship test, Lopez Lomong advanced through the preliminary round of the 800 meters at the U.S. track and field championships on Thursday.

“I just wanted to have fun with my fellow Americans,” the former “Lost Boy of Sudan” said with a big smile.

Lomong won't officially be sworn in as a citizen until July 6, but he was allowed to participate in this week's nationals because he will be an American before he represents his country in any international competition later this summer.

Lomong, a sophomore at Northern Arizona, won the NCAA 1,500 meters two weeks ago. He chose to run the 800 at the nationals to work on his speed.

Lomong finished third in by far the fastest of the four preliminary 800 heats with a personal best 1 minute, 46.28 seconds. It was the third-fastest time of all the qualifiers for Friday's semifinals. The only faster ones were the two who finished ahead of him in his heat, event favorite Nick Symmonds, who trains in Eugene, at 1:46.17 and Floyd Thompson in 1:46.24.

Lomong came to the United States under the “Lost Boys of Sudan” program in 2001 after spending 10 years in a Kenyan refugee camp. He said he was taken from his parents when he was 6 years old and imprisoned in a Sudanese rebel camp.

Three older boys escaped through a small hole in a fence and took him with them, Lomong said. According to Lomong, they ran for three days before encountering Kenyan border police, who took them to the refugee camp.

He expected to live his life in the camp but after writing an essay, he was chosen for the “Lost Boys” program and placed in the home of Robert and Barbara Rogers near Tully, N.Y.

He took the citizenship test in Buffalo, N.Y., after attending the wedding of the Rogers' son. The five Sudanese taken in by the Rogers after Lomong also were in attendance, the first time all of them had been together.

Lomong found out four years ago that his entire family also had made it out of Sudan and lives in Kenya. He speaks to them regularly and hopes to visit them this winter. It would be the first time they've seen him since he was snatched by the rebels 16 years ago.