The United States on Monday blacklisted Alexander Bastrykin, Russia's top investigator and a close aide to Russian President Vladimir Putin, and four other Russian officials for human rights abuses.

The sanctions, announced by the U.S. Treasury Department, are not tied to U.S. hacking allegations against Russia but to the 2012 U.S. Magnitsky Act for human rights abuses, U.S. officials said.

However, the move comes on top of a series of measures taken by the Obama administration in recent weeks to punish Russia for the hacking during the U.S. presidential campaign and for harassment of American diplomats.

Bastrykin heads the Russian Investigative Committee, the government body that decides whether to bring criminal charges. Also sanctioned were Gennady Plaksin and Stanislav Gordiyevsky, a state investigator, both tied to Sergei Magnitsky, an anti-corruption lawyer who died in 2009 after a year in a Russian jail.

The Magnitsky Act bars Russians believed to have been involved in his death or other severe human rights abuses from entering the United States, and freezes their assets there.

Also blacklisted were Andrei Lugovoy, a Russian lawmaker, and Dmitry Kovtun, both leading suspects in the murder of Russian spy and Kremlin critic Alexander Litvinenko in London in 2006.

Litvinenko fled Russia for Britain, where he was poisoned after drinking green tea laced with a rare but potent radioactive isotope at a London Hotel.

The inquiry found Lugovoy and Kovtun carried out the killing as part of an operation directed by the Russian Federal Security Service. Efforts to extradite both suspects to Britain have failed.