The law — retaliation for a US law punishing Russian officials implicated in the 2009 prison death of the whistle-blowing attorney Sergei Magnitsky — will take effect on January 1, the Kremlin said in a statement.
The United States reacted with disappointment.
“We deeply regret Russia’s passage of a law ending inter-country adoptions between the United States and Russia,” State Department spokesman Patrick Ventrell said in a statement, decrying the move as “politically motivated”.
Veteran Republican senator John McCain called the legislation “shameful and appalling”.
The US-based Freedom House think tank said, for its part: “It is immoral to hold orphaned children hostage in retaliation to targeted Americain sanctions against Russian human rights abuses.”
The highly contentious law is seen as the toughest piece of anti-US legislation during Putin’s 13-year rule and has prompted objections not just from activists but even some cabinet ministers.
Of particular concern are dozens of Russian children who are now in an agonising limbo. Having been prepared for US adoption they are now effectively banned from leaving for their new lives.
The Kremlin children’s rights envoy Pavel Astakhov said 52 such children should now go to Russian parents specially selected by regional governors.
“I believe they should be adopted in Russia,” Astakhov, a key backer of the legislation, told Interfax.
The law was passed by the State Duma, the lower house of parliament, and then by the Federation Council or upper house.
Putin said Thursday that he intended to sign it, ending days of speculation.
Rights activists and the Russian opposition slammed the law, accusing Putin of making children hostage to a political disagreement.
“Our poor children, orphans, will suffer because they are used as tokens in a political game between two countries,” veteran rights campaigner Lyudmila Alexeyeva told RIA-Novosti.
“That is immoral, it’s cannibalism.”
Pro-Kremlin lawmakers crafted the bill in a matter of days in response to a new US law sanctioning Russian officials implicated in Magnitsky’s death.
At first it was directed against Americans deemed guilty of violating the rights of Russians.
But the Duma later added two tough amendments, one banning US adoptions, the other banning Russian NGOs that have members with US citizenship or who had US financing.
Its passage revealed cracks in the Russian leadership between ministers wanting to get tough with the United States and those who favour more caution.
Foreign Minister Sergei Lavrov and the cabinet’s social affairs chief, Deputy Prime Minister Olga Golodets, both spoke out against it.
Reports have said that the law was authored by Vyacheslav Volodin, the hawkish first deputy chief of Putin’s Kremlin staff who headed his presidential campaign.
By apparent coincidence, a Moscow court on Friday also acquitted the former deputy chief of a Moscow prison where Magnitsky was held over causing his death by negligence.
Dmitry Kratov was the only Russian official still facing charges over the Magnitsky case.
Putin on Thursday had mounted a firm defence of the ban on US adoptions while accusing the United States of “acting brazenly and arrogantly” towards Russia.
He said those who believed that the law limited the opportunities of orphans failed to see the threats to Russian society posed by a steady outflow of children.
“There are lots of places in the world where living standards are higher than they are here,” said Putin.
“And what — are we going to send all our children there? Perhaps we should move there ourselves?”
He also raised the spectre of Russia going to “ruin” if it continued to allow foreigners to take care of its young, and slammed US authorities for denying Russian oversight to families that abuse Russian children.
In a statement, Russia’s Investigative Committee said it had nine current cases against American parents who have abused children adopted from Russia.
Russia’s foreign ministry decried in a statement what it called a US “propaganda campaign” against the adoption ban, saying that 19 deaths of Russian children adopted by Americans since 1996 is “only a tip of an iceberg”.
US families adopted nearly 1,000 Russian children last year and are the number one foreign destination of the country’s orphans.
Putin also signed a decree Friday on measures to protect orphans in Russia, part of a clear drive for all orphans in the country to be brought up in Russian families.
Astakhov has raised the prospect of Russia banning foreign adoptions altogether once the new orphan support programme is in place.
“We will be ready to do that (eliminate foreign adoptions) after the adoption of the federal targeted programme on orphans,” Interfax quoted Astakhov as saying on Thursday.