(Reuters) - The head of Russia's Orthodox Church urged citizens in a Christmas address on Monday to adopt Russian children after President Vladimir Putin signed a law last month barring Americans from doing so.

The ban retaliates for U.S. legislation designed to punish Russian human rights violators which Putin said is poisoning relations. Critics of Russia's legislation say Putin has made the welfare of children trapped in a troubled orphanage system hostage to political maneuvering, dimming their chances of finding loving homes or adequate medical care.