– Russia has been trying to intervene in the Democratic primaries to aid Sen. Bernie Sanders, according to people familiar with the matter, and Sanders said Friday that intelligence officials recently briefed him.

The disclosure came a day before the Nevada caucuses, where Sanders is a favorite, and followed revelations a day earlier that Moscow was interfering on President Donald Trump's behalf this year, as it did in 2016.

Sanders denounced Russia, calling President Vladimir Putin an "autocratic thug" and warning Moscow to stay out of the election. Drawing a contrast with Trump, he said he would stand against any efforts by Russia or another foreign power to interfere in the vote.

"The intelligence community is telling us they are interfering in this campaign right now in 2020," Sanders separately told reporters in Bakersfield, Calif., where he held a rally. "And what I say to Mr. Putin: 'If elected president, trust me, you are not going to be interfering in American elections.' "

He said he was briefed about a month ago. Asked why the disclosure came out now, he said, "I'll let you guess about one day before the Nevada caucus. Why do you think it came out?"

On Friday, Trump aggressively disputed that Russia was interfering on his behalf, saying it was part of a partisan campaign against him.

Russia's interference measures and their intensity remain murky, even as intelligence officials sound alarms.

In briefings to House Intelligence Committee members last week and to Sanders, officials said that Russia was actively interfering in the campaign, and people at the House briefing said intelligence officials reported Russia had a preference for Trump.

Revelations about the House briefing enraged Trump, who complained that Democrats would use Moscow's support for him against him, said people familiar with the matter. Days later, he replaced the acting director of national intelligence, Joseph Maguire, though administration officials have said it was not a direct result of the briefing.

Richard Grenell, the U.S. ambassador to Germany whom Trump appointed this week to replace Maguire, asked the agencies under his purview Friday to provide the raw information and analysis that went into the briefing, people familiar with the matter said. At the House briefing last week, senior intelligence officials said Russia was continuing its election interference, including intervening in the Democratic primaries.

Intelligence officials disputed that the briefer, Shelby Pierson, the nation's election security czar, said that Russia was actively aiding the re-election of Trump. She did say Russia is seeking to influence U.S. elections, including the primaries.

But people who heard the briefing said that the intelligence officers presenting the material said, in response to questions from lawmakers, that Russia was trying to get Trump re-elected.

Republicans have disputed that assertion, insisting that Putin simply wants to spread chaos and undermine the democratic system.

They have also argued that Sanders' gestures of peace toward the Soviet Union at the end of the Cold War might make him appealing to Putin.

But some current and former officials expressed doubt that Russian officials think that Sanders has some hidden affinity to Moscow. Instead, they said that a Russian campaign to support Sanders may ultimately be aimed at aiding Trump.

Moscow could potentially consider Sanders a weaker general election opponent for Trump than a more moderate Democratic nominee, according to two people familiar with the matter.

Russia also worked to support — or at least not harm — Sanders in 2016. Operatives at a Russian intelligence-backed troll factory were instructed to avoid attacking Sanders or Trump, according to a report by special counsel Robert Mueller and an indictment he secured of 13 Russians in that operation.

Both the indictment and Mueller's report quoted internal documents from the Internet Research Agency ordering operatives to attack Hillary Clinton's campaign. "Use any opportunity to criticize Hillary and the rest except for Sanders and Trump — we support them," the document said.