Washington CNN  — 

Sen. Bernie Sanders said Friday that his campaign was briefed about Russian efforts to help his presidential campaign, intensifying concerns about the Kremlin’s role in the US presidential race.

It remains unclear how Russia is attempting to help Sanders, according to The Washington Post, which first reported the effort. The revelation comes a day after it was reported that the US intelligence community believes Moscow is taking steps to help President Donald Trump win and at a time when Sanders is emerging as the Democratic front-runner.

Speaking to reporters in Bakersfield, California, Friday afternoon, Sanders confirmed that his campaign was briefed about the Kremlin’s efforts about a month ago and condemned Russia’s attempts to interfere in US elections.

“It was not clear what role they’re going to play. We were told that Russia, maybe other countries, are going to get involved in this campaign, and look, here’s the message to Russia: stay out of American elections,” Sanders said.

“And what they are doing, by the way, the ugly thing that they are doing, and I’ve seen some of their tweets and stuff, is they try to divide us up. That’s what they did in 2016 and that is the ugliest thing they are doing – is they are trying to cause chaos, they are trying to cause hatred in America.”

The Vermont senator speculated that the news broke on Friday afternoon in order to have an impact on Saturday’s Nevada caucuses, in which he is a leading candidate.

Two of Sanders’ centrist Democratic rivals seized on the news, with Michael Bloomberg’s campaign calling Russian support for Sanders a “no-brainer” for Moscow.

“They either nominate the weakest candidate to take on their puppet Trump, or they elect a socialist as President,” Bloomberg’s campaign tweeted.

And former Vice President Joe Biden told CNN’s Arlette Saenz in Las Vegas that the report indicates that Putin doesn’t want him to be elected.

Trump briefed

Trump has been briefed on the Russian effort to help Sanders, a White House official said. The timing of the briefing wasn’t clear.

At a rally in Las Vegas before the Post’s report broke, Trump suggested Moscow would prefer Sanders to win, not him, making no mention of the fact he’d been briefed about the matter.

“Doesn’t he (Russian President Vladimir Putin) want to see who the Democrat’s going to be? Wouldn’t you rather have, let’s say, Bernie? Wouldn’t he rather have Bernie, who honeymooned in Moscow?” Trump said.

At Wednesday night’s debate, Sanders was asked about online aggression from some of his supporters. Without mentioning the intelligence briefing, he replied, “All of us remember 2016, and what we remember is efforts by Russians and others to try to interfere in our elections and divide us up. I’m not saying that’s happening, but it would not shock me.”

Asked Friday by CNN’s Wolf Blitzer on “The Situation Room” why the Sanders campaign didn’t disclose Russia’s involvement, Ro Khanna, a national co-chair of the campaign, said the Vermont senator didn’t want to publicly reveal sensitive information. As for why Moscow would want to boost Sanders, Khanna said he has “no idea what motivates Vladimir Putin.”

Russia’s long-running effort to interfere in US elections

Russian interference in the last presidential election – which the US intelligence community believes was aimed at boosting Trump’s candidacy and hurting his opponent, Hillary Clinton – led to special counsel Robert Mueller’s investigation. Part of the election interference included a Russian government-linked troll operation that sought to help Trump’s candidacy and undercut that of Clinton in part by posting messages in support of Sanders.

Since 2016, US intelligence officials have continued to consistently warn about Russia’s ongoing efforts to interfere in American elections, noting threats to both the 2018 midterms and the 2020 presidential race.

On Thursday, CNN and other outlets reported that the intelligence community’s top election security official delivered a briefing to lawmakers last week warning them that the intelligence community believes Russia is already taking steps to interfere in the 2020 election to help Trump.

The President has repeatedly downplayed the threat as he has dismissed any suggestion that Kremlin influence played a role in his election. Referring to the latest Russia revelations at the Las Vegas rally, Trump said, “Here we go again.”

“I was told a week ago, they said, you know, they’re trying to start a rumor. It’s disinformation. That’s the only thing they’re good at. They’re not good at anything else. They get nothing done,” Trump remarked.

US intelligence officials, however, have continued to consistently warn about Russia’s ongoing efforts to interfere in American elections.

Last month, FBI Director Christopher Wray told the Senate Judiciary Committee that Russia was continuing to “engage in malign foreign influence” online with the goal of sowing division and discord, “and to generate controversy, to generate distrust in our democratic institutions in our electoral process.”

This story is breaking and will be updated.

CNN’s Donie O’Sullivan, Jim Acosta, Zachary Cohen, Dana Bash and Jeremy Herb contributed to this report.