NEW YORK — The number of foreign children adopted by Americans has dropped for the third year in a row, a consequence of tougher policies in the two countries — China and Russia — that over the past decade have supplied the most children to U.S. families.

Figures for the 2007 fiscal year, provided by the State Department on Friday, showed that adoptions from abroad have fallen to 19,411, down about 15 percent in just the past two years.

It's a dramatic change. The number of foreign adoptions had more than tripled since the early 1990s, reaching a peak of 22,884 in 2004 before dipping slightly in 2005, then falling to 20,679 in 2006.

"A drop in international adoptions is sad for children," said Thomas Atwood, president of the National Council for Adoption. "National boundaries and national pride shouldn't get in the way of children having families."

Adoptions from China, the No. 1 source country since 2000, fell to 5,453. That's down by 1,040 from last year and well off the peak of 7,906 in 2005. Two main factors lie behind this: an increase in domestic adoptions as China prospers and tighter restrictions on foreign adoptions that give priority to stable married couples between 30 and 50 and exclude single people, the obese and others with financial or health problems.

One consequence, adoption agencies say, is that the waiting time to complete an adoption from China has more than doubled to 24 months or more.

Adoptions from Russia also dropped sharply over the past year — from 3,706 to 2,310. Russian authorities suspended the operations of all foreign adoption agencies for several months earlier this year and have been reaccrediting them only gradually. Like China, Russia has been trying to boost the number of domestic adoptions.

U.S. adoptions from South Korea and Haiti also declined significantly, although the overall drop was partially offset by large increases in adoptions from Guatemala (up from 4,135 to 4,728), Ethiopia (732 to 1,255) and Vietnam (163 to 626).

Tom DeFilipo, president of the Joint Council on International Children's Services, said adoptions from Guatemala could decline over the coming year as its government — under intense international pressure — tries to impose tough new regulations on an adoption industry that was widely viewed as susceptible to fraud and extortion.

The State Department has advised Americans not to initiate adoption applications for Guatemala while that overhaul is under way. The proposed reforms are required under an international adoption treaty, the Hague Convention, which both Guatemala and the United States have agreed to adhere to starting next year.

Overall, DeFilipo — whose council represents many international adoption agencies — found reason for optimism in the new statistics.

"What you're seeing is fewer countries sending very large numbers of children and a broader range of countries participating," he said. "Over the long term, I think this is a healthy trend."

He mentioned Kenya, Peru and Brazil as countries not now among the major sources of children, but which might increase international adoptions in coming years.

Michele Bond, deputy assistant secretary of state for overseas citizen services, also viewed the new figures positively.

"Interest in intercountry adoption remains very strong," she said in a telephone interview. "People are increasingly well-informed. They're more likely to look at new countries instead of always looking at the same small number of countries."

By contrast, another adoption expert, Harvard law professor Elizabeth Bartholet, depicted the new numbers as "totally depressing."

She said China and Russia reflected a trend in which countries opened themselves up to international adoption, then scaled back. She attributed this in part to UNICEF and other international organizations encouraging countries to care for children within their homeland, even when domestic programs such as foster care might be inadequate.

"UNICEF is a major force," Bartholet said. "They've played a major role in jumping on any country sending large number of kids abroad, identifying it as a problem rather than a good thing."

UNICEF's child protection spokesman, Geoffrey Keele, said the U.N. agency does believe it is preferable to care for orphaned or abandoned children in their own countries if good homes could be found for them.

"The best interests of the child must be the guiding principle," he said. "We don't go about discouraging international adoption. We just want to be sure it's done properly."

Thomas Atwood, of the National Council for Adoption, said there should be no competition between domestic and international adoption. With an estimated 143 million orphans worldwide, he said, there was enough need to go around.

For U.S.-based adoption agencies, the biggest impact has been on those specializing in placing children from China.

The president of one of the largest such groups, Joshua Zhong of Colorado-based Chinese Children Adoption International, said the agency had placed about 620 children this year, down from about 1,200 in 2005, while average waiting times had increased from nine months to two years.

Some clients are so committed to adopting a Chinese child that they are willing to wait, Zhong said. "Others say forget about it."

For the second straight year, no Romanian children were adopted by Americans. The Eastern European country, which provided 1,119 children to U.S. families in 2000, has banned adoptions by foreigners, except for relatives.