Russia on Saturday said it was concerned by a US ruling that the death of an adopted Russian boy in Texas was an accident, fuelling a diplomatic row as several thousand people marched in Moscow demanding an end to all foreign adoptions. Russia's foreign ministry said it had learned of the US coroner's findings, which clear the boy's parents of wrongdoing, "with concern" and called on US officials to provide Moscow with the necessary documents, including the death certificate of three-year-old Max Shatto (born Maxim Kuzmin), to help shed light on the case.