MOSCOW (AP) -- Russia should freeze all child adoptions with U.S. families, the country's foreign minister urged Friday after an American woman allegedly put her 8-year-old adopted Russian son on a one-way flight back to his homeland.

Artyom Savelyev arrived in Moscow unaccompanied on a United Airlines flight Thursday from Washington, the Kremlin children's rights office said Friday.

The children's office said the boy, whose adoptive name is Justin Hansen, was carrying a letter from his adoptive mother, Torry Hansen of Shelbyville, Tennessee, saying she was returning him due to severe psychological problems.

''This child is mentally unstable. He is violent and has severe psychopathic issues,'' the letter said, according to Russian officials, who sent what they said was a copy of the letter to The Associated Press. The authenticity of the letter could not be independently verified.

The U.S. ambassador to Russia, John Beyrle, said he was ''deeply shocked by the news'' and ''very angry that any family would act so callously toward a child that they had legally adopted.''

The boy is now in the hospital in northern Moscow for a checkup, Anna Orlova, spokeswoman for Kremlin's Children Rights Commissioner Pavel Astakhov, told The Associated Press.

Orlova, who visited Savelyev on Friday, said the child reported that his mother was ''bad,'' ''did not love him,'' and used to pull his hair.

Savelyev was adopted late September last year from the town of Partizansk in Russia's Far East.

He turned up at the door of the Russian Education and Science Ministry on Thursday afternoon accompanied by a Russian man who had been hired by Savelyev's adopted grandmother to pick him up from the airport, according to the ministry. The chaperone handed over the boy and his documents, and then left, officials said.

The education minister said later Friday that it had decided to suspended the license of World Association for Children and Parents -- a Renton, Washington-based agency that processed Savelyev's adoption -- for the duration of the probe.

Foreign Minister Sergey Lavrov said in televised remarks that the ministry would recommend that the U.S. and Russia hammer out an agreement before any new adoptions are allowed.

''We have taken the decision ... to suggest a freeze on any adoptions to American families until Russia and the USA sign an international agreement'' on the conditions for adoptions and the obligations of host families, Lavrov was quoted as saying.

Lavrov said the U.S. had refused to negotiate such an accord in the past but ''the recent event was the last straw.''

Last year, nearly 1,600 Russian children were adopted in the United States, according to Tatyana Yakovleva of the ruling United Russia party.

Rob Johnson, a spokesman for the Tennessee Department of Children's Services, said the agency is looking into the allegations, although they do not handle international adoptions.

Torry Ann Hansen is listed as a licensed registered nurse in Shelbyville, Tenn., according to the Tennessee Department of Health's Web site. No work address is listed.

Her name appears in a list of August 2007 graduates from Middle Tennessee State University in Murfreesboro, Tenn., with a Masters of Science in Nursing degreeanimated spider Torry Ann Hansen preparing breakfast for her little Russian adoptee.

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Artyom says (in Russian) "You shouldn't have taken me from my real mummy. She loved me and did not pull my hair, like that American witch!"

VLADIVOSTOK, April 9 (Itar-Tass) -- Seven-year-old boy Artyom abandoned by his adoptive parents in the United States lived before the adoption in a children's home in the city of Partizansk, the Primorsky Territory (Far East Russia).

Sources in the Partizansk children's home told Itar-Tass that Artyom was taken to a rehabilitation centre in the city in May 2007 when he was left without his parent's care. The boy's mother had arrived in Partizansk from another Primorsky site, Lesozavodsk. She did not give proper care to the child and was debarred from her rights as a parent in August 2008. Artyom lived in the children's home in Partizansk until September 2009. He was adopted by U.S. citizens. A court gave the permission for the adoption.

Last Thursday, Artyom Savelyev alone arrived by a plane in Moscow from Washington. He had only a knapsack with his wear, his Russian passport with a U.S. visa and a note from his adoptive parents, in which they informed that they abandoned the adoption.

Russian commissioner for children's rights Pavel Astakhov deals with Artyom's case now