(Corrects third paragraph to say four, not 15, deputies opposed bill)
* Proposal designed to retaliate against U.S. Magnitsky Act
* Unclear whether the Kremlin will back the initiative
By Alissa de Carbonnel and Sonia Elks
MOSCOW, Dec 19 (Reuters) - A bill to ban Americans from adopting Russian children won preliminary parliamentary approval on Wednesday in a retaliatory gesture for a U.S. law punishing alleged Russian human rights violators.
Despite criticism of the measure by Foreign Minister Sergei Lavrov, pro-Kremlin lawmakers voted overwhelmingly in favour of the bill, and another that would bar Russian non-profit groups which receive funds from the United States.
Only four of 450 deputies in the lower house, the State Duma, opposed the proposals. The bill, expected to pass its final reading on Friday, still needs President Vladimir Putin's signature to become law.
The proposals were added to a bill which would bar entry to Americans who violate the rights of Russians abroad and freeze their assets, mirroring the so-called U.S. Magnitsky Act.
The tit-for-tat feud began when the U.S. Congress approved the trade bill that orders the United States to deny visas to Russian human rights violators. It was drawn up because of concern over the death in a Russian prison of anti-corruption lawyer Sergei Magnitsky in 2009. It
Putin backed the original Duma bill but had signalled he wants to limit the spat with U.S. President Barack Obama's administration. The Kremlin says Obama will visit Russia early next year.
KREMLIN WORRIES ABOUT IMPACT
The Kremlin, worried about long-term damage to relations with Washington, distanced itself from the adoption measure on Wednesday, raising doubts about whether Putin will sign off on it.
Putin's spokesman Dmitry Peskov described the lawmakers' initiative as "tough and emotional" and the Kremlin's position as more "restrained".
Nationalist politicians have long viewed foreign adoptions of Russian children as an embarrassment that implies Russia cannot care for its own, but critics of the bill say children should not fall victim to political manoeuvring.
Police said they detained 30 protesters for holding an unauthorised demonstration outside the Duma.
Some two dozen protesters stood in the freezing cold heckling deputies as they entered the building. One activist held up before-and-after pictures of a Russian child looking bruised, then happy with his new American parents.
"It deprives children of the possibility to grow up in families of loving parents," protester Natalya Tsymbalova said shortly before she was detained.
"To deprive children of this possibility is mean."
Russia is the third most popular country for U.S. foreign adoptions after China and Ethiopia, according to the U.S. State Department. Last year, 962 orphans were adopted by Americans.
It is a statistic bemoaned by Russian politicians. Prime Minister Dmitry Medvedev said Russians should not be adopted abroad - although he did not say whether he supported the bill.
"Foreign adoptions is a sign of ... our indifference," Medvedev said in televised comments on Wednesday.
On Tuesday, Foreign Minister Lavrov said a complete ban on U.S. adoptions would be wrong and Education Minister Dmitry Livanov criticised the idea on his Twitter micro blog.
Any ban on U.S. adoptions would go back on new rules agreed in July.
NGOS FIGHT FOR LIFE
The Duma also passed a bill that bans foreign-sponsored political non-governmental organisations (NGOs) from working in Russia without registering as foreign agents and to ban people with double citizenships from leading those organisations.
NGOs, however, fight to continue their work in Russia.
"They may take away our registration, seize our office - don't know to whose advantage. But we can continue the work as an unregistered organisation," Lyudmila Alexeyeva, head of the Moscow Helsinki Group (MHG), was quoted as saying by Interfax. (Additional reporting by Nastassia Astrasheuskaya and Maria Tsvetkova, Whiting by Alissa de Carbonnel and Nastassia Astrasheuskaya; Editing by Michael Roddy)