MOSCOW — President Vladimir Putin on Friday signed a law banning Americans from adopting Russian children, abruptly terminating the prospects for more than 50 youngsters preparing to join new families and sparking critics to liken him to King Herod.

The move is part of a harsh response to a U.S. law targeting Russians deemed to be human rights violators. Although some top Russian officials including the foreign minister openly opposed the bill, Putin signed it less than 24 hours after receiving it from Parliament, where it passed both houses overwhelmingly.

The law also calls for the closure of non-governmental organizations receiving American funding if their activities are classified as political — a broad definition many fear could be used to close any NGO that offends the Kremlin.