A U.S. Treasury Department official is accusing Russian President Vladimir Putin of corruption, the first time an American official has publicly and directly accused Putin of impropriety. The Treasury undersecretary for terrorism and financial intelligence, Adam Szubin, told a BBC investigations unit in a report published Monday that the U.S. government has known of Putin’s corruption for “many, many years.”

“We've seen him enriching his friends, his close allies, and marginalizing those who he doesn't view as friends using state assets,” Szubin said. “Whether that's Russia's energy wealth, whether it’s other state contracts, he directs those to whom he believes will serve him and excludes those who don't. To me, that is a picture of corruption."

The Kremlin called the allegations “pure fiction.” Officially, Putin makes $110,000 a year from his government job, but that is likely not reflective of his actual wealth and income, according to critics. An unpublished 2007 CIA report pegged his personal wealth at about $40 billion.

A former fund manager in Russia, Bill Browder, said Putin’s personal wealth could be as high as $200 billion. “After 14 years in power of Russia, and the amount of money that the country has made, and the amount of money that hasn't been spent on schools and roads and hospitals and so on, all that money is in property, bank, Swiss bank accounts, shares, hedge funds, managed for Putin and his cronies,” Browder told CNN's "Fareed Zakaria GPS" last year.

For reference, the Forbes list of the world's 500 wealthiest people from 2015 placed Microsoft founder Bill Gates as the wealthiest individual alive with a net worth of $79.2 billion.

Szubin's accusations come after a separate damning assessment in the United Kingdom, where a public inquiry concluded last week that Putin had “probably” approved of the murder in London of former Russian spy Alexander Litvinenko. Litvinenko was a Russian spy who was assassinated in 2006 with radioactive polonium-210 that is believed to have been put into his cup of tea. He was a fierce critic of Russia at the time and it was discovered that he had been receiving a paycheck from the British secret service MI6. His death is often said to be connected to Putin.