Several protesters were arrested outside the upper chamber of Russia’s parliament on Wednesday morning as it prepared to vote on a measure banning Americans from adopting Russian children.
They complain it will deprive children of an opportunity to escape from the often dismal conditions in Russian orphanages.
The bill has been designed as a retaliation against a new US law imposing sanctions on Russians deemed to be human rights violators.
It was endorsed by the lower house last week and will be sent to President Vladimir Putin to sign if the Federation Council votes for it as expected.
The President has not yet committed to signing the bill but has called it is a legitimate response to the new US law.
UNICEF estimates there are around 740,000 orphans and abandoned children in Russia.
More than 60,000 children have been adopted by Americans in the past 20 years, although the annual number has plummeted recently.