Russia threatened to suspend all child adoptions by U.S. families Friday after a seven-year-old boy adopted by a woman from Tennessee was sent alone on a one-way flight back to Moscow with a note saying he was violent and had severe psychological problems.

The boy, Artyom Savelyev, was put on a plane by his adoptive grandmother, Nancy Hansen of Shelbyville.

Artyom Savelyev, 7, is accompanied by Russian authorities after his adoptive U.S. mother sent him back to Moscow on a one-way flight. (Daily Mail)

Russian Foreign Minister Sergey Lavrov called Hansen's actions "the last straw" in a string of U.S. adoptions gone wrong, including three in which Russian children had died in the U.S.

The cases have prompted outrage in Russia, where foreign adoption failures are reported prominently. Russia's main TV networks ran extensive reports on the latest incident in their main evening news shows.

The Russian Education Ministry immediately suspended the licence of the group involved in the adoption — the World Association for Children and Parents, a Renton, Wash.-based agency — for the duration of the investigation.

In Tennessee, authorities were investigating the adoptive mother, Torry Hansen, 33.

'I am sorry to say that ... I no longer wish to parent this child.'

—Torry Hansen, in a letter published in the Daily Mail

The Russian government office in charge of children's rights says Artyom was carrying a letter from Torry Hansen.

According to a copy of the letter published in Britain's Daily Mail, Hansen said she adopted Artyom in September but was lied to by workers at the Russian orphanage from where he came.

"This child is mentally unstable," the letter reads. "He is violent and has severe psychopathic issues.

"After giving my best to this child, I am sorry to say that for the safety of my family, friends and myself, I no longer wish to parent this child."

Nancy Hansen said Friday the family had paid a man $200 to pick the boy up at the airport in Moscow and take him to the Russian Education and Science Ministry.

She said it wasn't child abandonment because a stewardess was watching Artyom on the flight and a reputable person picked him up in Russia.

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."

'Last straw'

In the past, Russia has tried to get the U.S. to sign an accord outlining conditions for international adoptions and the obligations of host families, but to date, the U.S. has refused.

"The recent event was the last straw," Lavrov said. "We have taken the decision ... to suggest a freeze on any adoptions to American families until Russia and the U.S.A. sign an international agreement."

The boy was taken to hospital in northern Moscow for a checkup, Anna Orlova, spokeswoman for Children Rights Commissioner Pavel Astakhov, told The Associated Press.

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

Nancy Hansen said the child was violent and angry with his adoptive mother in the U.S.