MOSCOW — Russia's parliament on Wednesday gave overwhelming preliminary approval to a measure banning Americans from adopting Russian children, a harsh retaliatory move against U.S. human rights legislation.

Top Russian officials have expressed unease about the proposal, an apparent indication that the Kremlin opposes the move.

The lower house of parliament, the State Duma, on Wednesday approved the second reading of a bill responding to the U.S. legislation. The proposed adoption ban was not part of the original bill, but was added as an amendment.