Heather and Aaron Whaley just wanted to start a family with a four-year-old Russian girl nicknamed Addie who they found on the Internet but have yet to see in person.

Never did they expect to find themselves caught up in a souring of relations between Moscow and Washington over human rights.

The Whaleys are among several US couples whose pending adoptions of Russian children are in limbo after President Vladimir Putin signed legislation barring Americans from adopting Russian youngsters.

"We're both very worried and stressed right now," Heather Whaley told AFP on Friday as she and her husband drove back to their Frederick, Maryland home after a Christmas holiday in her native Alabama.

"President Putin originally said he would allow families which are 'in process' to complete their adoptions within the next year," she said. "I don't know if he'll hold to that... but we're hopeful."

When Putin signed the adoption ban earlier Friday, 46 Russian children had been cleared by Russian courts for adoption by American families, said Megan Lindsey of the National Council for Adoption, an advocacy group.

Around 1,500 other applications were at some stage of being processed.

The Whaleys, devout Christians who say God blessed them "with a heart for children," discovered Addie -- the girl's Russian given name is Regina -- last February on a website featuring Russian kids available for adoption.

Someone else had applied to take her but dropped out after learning that Addie -- like many unwanted Russian children -- had special needs, something that did not at all deter the Whaleys.

"She's very, very tiny for her age -- she's only 24 pounds (11 kilograms), which is about the size of an 18-month-old," said Heather Whaley, who has two adopted sisters and works part-time with youngsters with special needs.

"We also know that she is developmentally delayed" and unable to speak at a level on a par with children her age, she added.

The Whaleys started the paperwork with World Links International, an adoption agency in Scranton, Pennsylvania, and launched a blog (www.bringaddiehome.com) to chronicle their journey.

They also drained their life savings, and reached out to family and friends, to help cover the estimated $65,000 in adoption fees and travel expenses to bring Addie to America.

"We had felt that was going to be our biggest worry, just raising a huge amount of money," Whaley said.

They had been planning to travel to Vladivostok, in Russia's far east, in early 2013 to actually see Addie in the flesh on the first of three visits that would-be adoptive parents are required by Russian law to make.

"Russia is one of the hardest countries to adopt from. Their regulations and red tape are excruciating," said Whaley, who has decorated her home with pictures of the smiling child.

In the meantime, the Whaleys' home has been inspected by adoption officials, and a pediatrician at Johns Hopkins University has gone over Addie's medical file with a fine-tooth comb.

Tatiana Suslin, chief executive of World Links International, said her agency has 16 families whose applications to adopt Russian children are currently in a bureaucratic pipeline that typically takes a year to clear.

"They are just struggling," she told AFP. "They are so upset. What can you tell them?"

Two of those families won Russian court approval of their adoption applications on December 7, but even they are not 100 percent sure their children will be free to depart Russia as planned.

"Those children, they are hostages of a political situation," Suslin said.