MOSCOW (AP) -- Russian President Vladimir Putin has fired the latest salvo in an increasingly contentious relationship with the U.S.
He's signed a bill banning Americans from adopting Russian children as part of a harsh response to a U.S. law targeting Russians deemed to be human rights violators.
The adoption ban has been criticized, even in Russia.
UNICEF estimates that there are about 740,000 children not in parental custody in Russia,.
The U.S. is the biggest destination for adopted Russian children. More than 60,000 of them have been taken in by Americans over the past two decades.