The nation's newest citizens took over the spotlight yesterday at the Greatest Show on Earth, outshining, for at least a few moments, the star-spangled performance of the ringmaster.

The 22 children, ranging in age from 21 months to 15 years and adopted by American families, received their certificates of U.S. citizenship at the D.C. Armory, which has been converted into a three-ring arena for the Ringling Bros. and Barnum & Bailey Circus.

"This is a nice way for us to feel like our family is welcome," said Andrea Usiak of Arlington, who, with her husband, Douglas Stearn, adopted an infant two years ago from Colombia. The toddler, born Juan Cardona Munoz, is now Zachary Cardona Stearn.

"It's kind of nice to have something special and [know] that he's welcome to this country and for him to be a full member, not just of our family, but our community," Usiak said.

The youngsters, who each received a fake red nose from a clown and miniature American flags from immigration officials, were born in Bolivia, China, Colombia, Guatemala, Indonesia, Kazakhstan, Poland, Russia, the Ukraine and Vietnam.

After the ceremony, they got to see how elephants are prepped for the big show, and they took part in what the circus calls "the world's largest balancing class." Then they were treated to an evening performance of the circus.

Zachary was not the only one with a new name and a new home. This was the seventh year that immigration officials have used the circus as a setting for the children's citizenship ceremony, a tradition that dates to the mid-1980s. But it was the first to be sponsored by the Bureau of Citizenship and Immigration Services, the former Immigration and Naturalization Service that was under the Justice Department. The citizenship bureau is now part of the Department of Homeland Security.

"The wonderful thing about America is that we welcome children into our families . . . who will take our country in new directions that we can't even imagine right now," said Susan Neely, assistant secretary for public affairs for the Department of Homeland Security. With her at the swearing-in was her son, Ben, whom she and her husband adopted as an infant from Cambodia two years ago.

During the ceremony for the families, which began with the ringmaster leading them in singing the national anthem, a special children's oath of allegiance was recited. The new citizens vowed to "be true to the United States . . . support its Constitution, obey its flag and defend it against all enemies." Phyllis A. Howard, director of the citizenship bureau for the Washington district, handed each child -- or a parent -- a certificate of citizenship.

Since February 2001, when the federal Child Citizenship Act was passed, foreign-born children adopted by American parents have been granted automatic citizenship. Previously, such children entered the United States as legal permanent residents and received green cards, and their parents applied for their citizenship. Now they can get U.S. passports immediately, and there is no requirement to apply for citizenship. The ceremony yesterday simply provided an opportunity to get a certificate.

"It's her proof," Marla Belvedere said of her daughter, Laura Aizhan Belvedere, whom she and her husband, Christopher, adopted from Kazakhstan two years ago. "We know she's a citizen, but with the world being a crazy place the way it is, I want to have the document for her."

Yesterday, Laura, a month shy of 3 and wearing a purple and gold brocade dress from Mongolia, turned to her father and said, "Daddy, where's the zoo?" Her father said, "Not the zoo. We're at the circus."

Her middle name, Aizhan, is a Kazak word that means "soul of the moon."

The ceremony is also "a great way of honoring parents and the adoptive children, because it's been a long process," said Ernestine Fobbs, a spokeswoman for the Washington district office of the citizenship bureau.

"A lot of these children were in orphanages or abandoned, and the parents have gone through a long process in order to adopt them," she said.

For instance, the Belvederes, who live in McLean, traveled 58 hours to meet their daughter in an orphanage in Taraz, Kazakhstan. And Dana Taylor of Manassas went to the foothills of the Himalayas last May to pick up her daughter, Guan Jiang Qi, in an orphanage in Kunming, Yunnan, in southwest China. She is now Dylin Taylor, and yesterday she wore a red, white and blue gingham dress that matched her miniature flag.

Taylor, who decided to adopt as a single woman, said she was thrilled to get the certificate for Dylin, who turns 3 next month.

"To me, it's the final proof that she absolutely is a citizen. She's definitely going to be raised as a U.S. citizen, of course, with the little bit of Chinese culture that I can offer her," Taylor said. "But there's no denying it: She will be an American child."

Derek and Dulce Wahdan pose with clown Cezary Skarzynski. Dulce, who is from Guatemala, received her citizenship papers.Brian Stroud, 8, a native of Indonesia who now lives in Ashburn, is welcomed into the ring by Jumping Jon Weiss, an acrobat for the Ringling Bros. circus.Mychi Haan, 19 months, who was born in Vietnam, plays with her new mother, Frankie Haan of Arlington.