Russia's upper house of parliament Wednesday unanimously backed a bill barring Americans from adopting Russian children, leaving the controversial measure in the hands of President Vladimir Putin.
The rubber-stamp hearing cleared the last legislative hurdle for a bill representing one of the toughest pieces of anti-US legislation to emerge during Putin's 13 years in charge.
The Russian strongman has expressed sympathy for the measure -- drafted in retaliation for a new law sanctioning Russian officials implicated in the prison death of lawyer Sergei Magnitsky in 2009 -- without explicitly committing to signing it.
The bill has passed the three required readings in the State Duma lower house despite protests from rights advocates, the United Nations and even the Russian foreign ministry.
Russian actor Konstantin Khabensky underlined the unease in Russia about the law by appearing next to Putin during a Kremlin awards ceremony wearing a button reading "Keep children outside politics."
The ceremony occurred moments before the Federation Council -- made up exclusively of Putin allies and ruling party members -- passed the measure in a 143-0 vote after speakers took turns decrying US policies towards Russia.
"I believe that any foreign adoption is detrimental to our country," children’s rights commissioner Pavel Astakhov said. "A country as great as Russia should not be selling its children."
The bill also includes a provision forbidding Russian political organisations from receiving US funding.
"It is now clear that Putin intends to sign this," said veteran human rights campaigner Lev Ponomaryov. "This reminds me of Soviet times."
The White House said it intended to raise concerns with both parts of the legislation at future meetings with Russian officials.
"Children should have every opportunity to grow up in loving families," US President Barack Obama's national security staff said. "Their fate should not be linked to unrelated political considerations."
UNICEF executive director Anthony Lake issued a similar plea, saying the government must make sure the "current plight of the many Russian children in institutions receives priority attention.
"We ask that the government of Russia, in its design and development of all efforts to protect children, let the best interests of children -- and only their best interests -- determine its actions."
Moscow's pointman on US relations conceded that Wednesday's vote was likely to add to difficulties that have emerged since Putin's return to a third Kremlin term in May.
"This weight, this ballast will act as a drag on our relations. There is no doubt about that," Interfax quoted Deputy Foreign Minister Sergei Ryabkov as saying.
"With everything that has been happening, the backdrop (to our relations) going into the new year is very bad."
The legislation emerged after Obama signed into law the so-called Magnitsky Act which pays tribute to a Russian lawyer who died in custody after exposing a $235 million police embezzlement scheme.
The law blacklists dozens of Russian officials allegedly involved in his death and freezes their assets in the United States.
Magnitsky's employer Hermitage Capital -- once Russia's largest Western investment fund -- and family both believe the 37-year-old was tortured to death.
But Russian prosecutors this week dropped charges against the only person on trial in the case.
Cabinet members such Foreign Minister Sergei Lavrov have spoke out against the adoption bill.
The deputy prime minister in charge of social affairs Olga Golodets also wrote to Putin voicing her objections, while Putin's human rights council condemned the bill as potentially unconstitutional.
Putin now has two weeks to sign the legislation.
The United States remains the number one foreign destination for orphans in Russia -- which since Soviet times has relied on state-run homes for children and has a weak tradition of adoptions.
A total of 956 Russian children travelled to the United States last year to be adopted out of the 3,400 who found families abroad. Russians recorded 7,400 adoptions in the same period.
Astakhov said 46 children whose US cases are pending would not be able to travel to their new homes if the legislation takes effect January 1 and would be given "priority assignment" for adoption by Russian families.