Eric Risberg, Associated Press
Exchange participant Tanya Kazyra of Belarus has spent nine summers at her host family's home in Petaluma, Calif.

PETALUMA, Calif. — In the Zapata family photos, it's hard to separate Tanya Kazyra from the other children. They're shown hugging in portraits, smiling in Christmas cards, playing together.

The 16-year-old from Belarus has spent nine summers in this wine country town as part of an exchange program for children from regions affected by the Chernobyl nuclear accident. But now she's refusing to leave, causing a rift in diplomatic circles and prompting her native country to halt its exchange and adoption programs to the U.S.

"This is my family," Tanya says, and the Zapatas agree.

"She's called us mom and dad since she was 8 years old," said Debra Zapata.

At age 16, Tanya's too old to continue in the program. And she says the life waiting for her at home is grim. A court order removed her from her parents' care as an infant, and she was raised by a grandmother, who shielded her from her father's violence and drug abuse, she said.

"There, my life is too hard," Tanya said, explaining that she's received her grandmother's blessing to do whatever she felt was best. "I love my country, and I love my grandma. But life is not really good. I have a family here."

Tanya's decision to outstay the program's Aug. 5 end initially led to accusations of kidnapping, with police visiting the Zapata residence to make sure the girl wasn't being held against her will. Her visa expires in December, and she's requested an extension by immigration authorities.

This is the first time an exchange participant has refused to return home, but it has led to the government suspending the trips, said Oleg Kravchenko, charge d'affaires at the Belarus Embassy in Washington.

"As a party responsible for these kids, we do not find ourselves in position to let them go here anymore," he said.

An envoy of the Belarus ministry of foreign affairs flew to Petaluma to speak with Tanya, while Belarusian representatives say they're talking with the State Department, seeking the girl's prompt return and a guarantee that this won't happen again.

State Department officials say they can't discuss the details of this case but confirmed they're in discussion with the government of Belarus regarding one of its exchange programs.

Relations between the two countries were already frayed by U.S. sanctions and tensions over detainees described by Americans as political prisoners. Both sides recalled their ambassadors in March.

No resolution emerged from meetings this week, and as negotiations continue, pressure mounts on the Zapatas and Tanya. Other families who have hosted children over the years are afraid they won't have another chance to see kids they've grown to love.

Up to 2,000 children from regions still suffering from the fallout of the Chernobyl disaster get health, dental and vision care as well as a carefree summer through programs such as this every year since 1991, said Cecelia Calhoun, Belarus liaison for the Children of Chernobyl United States Alliance.

"Thousands and thousands have benefited from this," said Calhoun. "It's all very unfortunate."

The Zapatas and their lawyer note the decision to halt the program came from the Belarusian government. Thousands of American children go abroad, and foreigners come as part of exchange programs, and on occasion, some don't return on schedule, said the Zapata's attorney, Christopher Kerosky.

"It happens, and it never leads to a diplomatic crisis," he said. "Isn't this excessive? Why is the government overreacting like this?"

He said blaming it on Tanya puts unfair pressure on the teenager, whose life in the industrial town of Borisov has been rough except for monthly phone calls from the Zapatas and the knowledge of summers far away in Petaluma.

Debra Zapata knows the Belarusian government is pushing hard, but the nurse and mother of three says she's not wavering either.

"Tanya is part of our family, and we'll help with anything, no matter how hard it is," she said.