The death of a young boy adopted from Russia at his Texas home was an accident and the bruises found on his body were ruled "self-inflicted," US media reported Friday, citing a corner's report.

The Kremlin's children's rights envoy Pavel Astakhov sparked a firestorm last month by declaring that Max Shatto, born Maxim Kuzmin, was murdered by his adoptive parents who were doping him with prescription drugs.

But four doctors who reviewed his autopsy results cleared his adoptive parents of wrongdoing, CBS 7 news reported.

The autopsy found that he died from a "lacerated artery" due to blunt force trauma in his abdomen and had no drugs in his system.

The coroner -- who was not immediately available for comment -- also noted that Shatto had a mental disorder and that caused him to hurt himself.

The boy's death exacerbated a diplomatic row triggered by the passing by the United States late last year of a bill targeting Russian officials with sanctions over the prison death of Russian lawyer Sergei Magnitsky.

Russia retaliated with a ban on all US adoptions, saying Russian children in the United States were abused and even murdered by their adoptive parents.

Russian officials have blamed US authorities for failing to prosecute US parents who harm Russian adoptees, justifying the adoption ban.

The State Duma, Russian parliament's lower house, last month adopted a special appeal to the US Congress asking for help in returning the boy's younger brother, who remains with their adoptive parents in Texas.

The US ambassador to Moscow Michael McFaul responded by calling on Russian officials to stop "sensational exploitation" of the tragic death.

[Image via Agence France-Presse]