Demonstrators hold posters reading "There is no place for juvenile justice in Russia," "I want all children be happy" during a massive rally to back the ban on U.S. adoptions of Russian children in Moscow, Saturday, March 2, 2013. Russia voiced strong skepticism Saturday about the U.S. autopsy on Max Shatto, a 3-year-old adopted Russian boy in Texas and demanded further investigation as thousands rallied in Moscow to support the Kremlin ban on U.S. adoptions of Russian children. AP Photo/Alexander Zemlianichenko Demonstrators hold portraits of adopted Russian children who died in U.S., during a massive rally in Moscow, Saturday, March 2, 2013. The poster at left reads: "Vitya Tulimov died in 2000 in New Jersey at the hands of adoptive parents." A poster at right reads "Dima Yakovlev." Demonstrators carry Russian flags and a huge poster reading "March in Defense of Children" during a massive rally in Moscow, Saturday, March 2, 2013. Max Shatto's death in January, ruled accidental, came a month after Moscow passed a ban on international adoptions in retaliation for a new U.S. law targeting alleged Russian human rights violators. Russian officials have pointed at Max's case to defend the ban, which has drawn strong public criticism. Children rights ombudsman Pavel Astakhov, who initially claimed that the boy had been "murdered" by his adoptive parents, tweeted that Russia should "demand convincing proof." Pro-Kremlin groups rallied in central Moscow to back the ban on U.S. adoptions of Russian children and call for more adoptions by Russian parents. Protesters held signs with pictures of adopted Russian children who died in the U.S. in recent years and wore ribbons in the colors of the Russian flag with slogans demanding Max's half brother Kirill be returned to Russia. Today people are telling us that Maxim supposedly maimed himself to death with a blunt instrument and damaged his own internal organs. That's a slap in the face of our country and our people," Irina Bergset, one of the march's organizers, said in a speech at the rally. Olga Batalina, a lawmaker from the Kremlin-backed United Russia party who reportedly authored the adoption ban, said Saturday that Russia should work towards liquidating orphans as a class by focusing on state-sponsored "basic moral values." Organizers claimed upwards of 20,000 attended, though police estimated numbers at 12,000. Two people were arrested. Approximately 25,000 attended a protest against the U.S. adoption ban in January. The atmosphere at Saturday's march was festive and rather bizarre. Marchers included large groups of old people in fur coats, members of obscure esoteric communist parties, and organizations that had no apparent link to the march, including the Gardener's Union and a group for victims of the 1986 Chernobyl nuclear disaster in Ukraine. Organizers herded people into columns and handed out balloons as eerie pop music sung by children wafted over loudspeakers. "I came here because Americans beat our children they adopt," Ivan Levin, a participant, said. Ideally, that shouldn't happen. A significant number of demonstrators had been bused in from as far as hundreds of miles away from Moscow, a common tactic to boost numbers at pro-Kremlin rallies. In the days leading up to the march, classified ads and letters on United Russia stationery appeared online offering people money to attend or demanding that business owners and university directors bring 50 people. Organizers vehemently denied that anyone had been paid or coerced to attend. The independent RBK news agency, however, posted photos on Twitter of what it said were marchers being paid after the march ended. He said that Russian diplomats had taken action to return the boy, but acknowledged that it would be difficult to achieve because the adoption process was in accordance with Russian law. Kuzmina said during the show that she gave up drinking, had found a job and pledged to fight to regain custody of Kirill. AP writers Vladimir Isachenkov and Laura Mills contributed to this report.