WASHINGTON -- The U.S. Treasury has hit the leader of Chechnya with financial sanctions under the Magnitsky human rights law, accusing him of torture and "extrajudicial killings," and another Chechen security official of involvement in the "antigay purge" that targeted gay and bisexual men in the Russian region earlier this year.

Ramzan Kadyrov, whose name was added to the Treasury's Office of Foreign Assets Control (OFAC) on December 20, is one of the most prominent Russian officials to be added to the list established by the 2012 law that aims to punish Russians alleged to be involved in human rights violations.

Since its passage, the law has infuriated the Kremlin, which retaliated in 2013 with a sweeping ban on American parents adopting Russian children.

Four other individuals were also added to the sanctions list: Ayub Katayev, Yulia Mayorova, Andrei Pavlov, and Aleksei Sheshenya. A total of 49 people have now been named to the public list, subjecting them to various financial and travel restrictions. An unknown number of others are believed to be listed on a classified list, as well.

Kadyrov and Katayev were targeted for "gross violations of internationally recognized human rights" in Chechnya. The Treasury Department identified Katayev as a law enforcement officer in Chechnyа.

"We will continue to use the Magnitsky Act to aggressively target gross violators of human rights in Russia, including individuals responsible for extrajudicial killings, torture, and other despicable acts," John Smith, director of the Treasury sanctions office, said in a statement.

On a conference call with reporters on December 20, a senior U.S. State Department official said that "one or more of Kadyrov's political opponents were killed at his direction."

By being listed on the Magnitsky Act, the individuals are blocked from much of the international banking system. Any assets they may have in the United States could also be frozen.

In a posting to his Instagram account, his preferred means of public statements, Kadyrov responded with a mocking commentary:

"The U.S. Treasury has nothing better to do, just like a cat who itches in one place. And so, I was banned from entering America. And am I going to apply for a visa, do I have assets in U.S. banks? I said it before, but again I will repeat it for the especially forgetful that I would not have gone to the U.S.A. if all the foreign currency reserves of the country were promised to me as a prize."

There was no immediate reaction to the announcement from Moscow.

The Russian newspaper Novaya Gazeta earlier this year was the first to document that police in Chechnya rounded up, tortured, and humiliated dozens of gay or bisexual men.

The report was later corroborated in part by RFE/RL as well as by Human Rights Watch, which said the "antigay purge" lasted from late February until at least early April and that "it was ordered and conducted by officials in Chechnya."

Kadyrov himself denied the accusations, as did the Kremlin.

The other three were accused of involvement in the criminal conspiracy exposed by Sergei Magnitsky, a Russian whistle-blower for whom the law is named.

The United States passed the Magnitsky Act in 2012, punishing people alleged to be connected to Magnitsky's death and the massive tax-fraud scheme he helped uncover.

Magnitsky was employed by British-American financier William Browder when he was arrested and charged with the $230 million tax-fraud scheme that he helped uncover.

He died in a Moscow jail in 2009. His friends and family say he was tortured while detained.

A Council of Europe investigation concluded the conditions leading up to his death amounted to torture.

In the wake of the 2012 U.S. law, Moscow banned American parents from adopting Russian children. Congress later passed an expanded version of the Magnitsky law, amid a secretive lobbying campaign in Washington aimed at undermining the facts of the Magnitsky case.

The most prominent Russian official on the list is Aleksandr Bastrykin, the head of the powerful Investigative Committee and an ally of President Vladimir Putin.

Mark Najarian contributed to this report from Washington