* 3-year-old may have been badly beaten -Russian officials
* U.S. says law enforcement investigating Texas death
* Case could inflame adoption dispute with Washington (Adds State Department comments)
By Sonia Elks
MOSCOW, Feb 19 (Reuters) - Russian investigators have opened an inquiry into the death of an adopted 3-year-old boy in the United States in a case that could aggravate a row with Washington over adoptions in Russia.
Russian officials said they are concerned that Maxim Shatto, whose Russian name is Maxim Kuzmin, may have been badly beaten before his death on Jan. 21 in his home in Texas.
Moscow seized on the case as justifying a new law banning adoptions of Russian children by Americans, a measure that has escalated a tit-for-tat row with Washington over trade and human rights.
"I would like to draw your attention to yet another case of inhumane treatment of a Russian child adopted by American parents," Konstantin Dolgov, the Russian Foreign Ministry's human rights representative, said in a statement.
Shatto was adopted with his younger brother Kirill from an orphanage in Pskov in northwest Russia.
U.S. authorities said the circumstances surrounding the boy's death were under investigation, and the results of an autopsy were pending, according to the Ector County Sheriff's office.
Texas child welfare authorities were also investigating allegations of child abuse and neglect in the case, a process that can take a month or more, Texas Department of Family and Protective Services spokesman Patrick Crimmins said on Tuesday.
Crimmins said one of the main priorities was ensuring the safety of the boy's 2-year-old brother, who remains in the home.
Russia's Investigative Committee, a government body in charge of criminal investigations, has opened 10 investigations into actions suspected of "threatening the lives and health" of Russian-born children in the United States.
"The Investigative Committee will take all necessary measures to ensure that the killer of a Russian child suffers the most severe punishment," it said in a statement.
In Washington, U.S. State Department spokeswoman Victoria Nuland said it was local law enforcement's responsibility to investigate the boy's death.
"It is a terrible tragedy that this child has died. But none of us, not here, not anywhere in the world, should jump to a conclusion about the circumstances until the police have had a chance to investigate," Nuland told reporters at her daily briefing.
She said the State Department had been working with the Russian consulate in Houston and the embassy in Washington to put Russian officials in touch with authorities in Texas.
The United States has previously refused to hand over data to Russian investigators, and the two countries do not have bilateral extradition agreements, meaning the Russian probe is likely to be purely symbolic.
Russia banned U.S. adoptions as of Jan. 1 in retaliation for the U.S. Magnitsky Act, drawn up over concern about the death in a Russian prison of anti-corruption lawyer Sergei Magnitsky in 2009. The act will deny visas to Russians accused of human rights abuses and freeze their assets in the United States.
The head of the Russian lower house of parliament's committee for family, women and children called for all children who had already been adopted in America to be returned to Russia.
American families adopt more Russian children than those of any other country, with more than 60,000 cases since the 1991 collapse of the Soviet Union, including 962 in 2011.
Moscow has said its ban was justified by the deaths of 19 Russian-born children adopted by U.S. parents in the past decade, and what they perceive as lenient treatment of the parents.
The U.S. embassy in Moscow did not immediately comment. (Additional reporting by David Bailey and Arshad Mohammed; Editing by Jason Webb, Bob Burgdorfer and Mohammad Zargham)