New York CNN  — 

Sen. Kamala Harris has claimed her presidential campaign is being targeted on social media by Russian bots. But while US intelligence officials say Russian disinformation campaigns targeting Americans continue, verified evidence of attacks on specific candidates has yet to publicly emerge.

Harris’ claims come as “Russian bots” have become a catchall description, for some, of any disinformation spread online. Democrats could even potentially view the perception that they have been targeted by Russian trolls as politically advantageous – another way to contrast themselves to President Donald Trump, who has publicly sowed doubt about the veracity and implications of Russian cyber meddling, despite warnings from intelligence officials.

A Twitter spokesperson told CNN that the company had no evidence that Harris was the target of state-backed bots. Facebook would not say if it had found any Russian activity relating to Harris or other Democratic candidates.

Both Twitter and Facebook infamously failed to detect expansive disinformation campaigns run from Russia in 2016. Faith in the companies’ ability to detect covert information campaigns may be justifiably low and it may very well later emerge that some of the attacks on Harris emanate from Russia. However, the senator appears to have insufficient evidence to make the assertion as she did.

In the years since America learned Russia had run a vast cyber and social media offensive targeting the 2016 US presidential election, politicians, media outlets, researchers and academics have sometimes incorrectly attributed nefarious online activity to Russia. Disinformation campaigns run by domestic actors, Iran and other nation-states can sometimes be overshadowed by the propensity to falsely attribute activity to Russia.

Harris faced a flood of attacks that sought to undermine her racial identity during last month’s presidential debate after she recounted being bused to school as a child.

CNN documented how the attacks had been festering online for months, before being elevated to the mainstream on debate night, when Donald Trump Jr. shared a tweet sent by one user with the assertion, “Kamala Harris is *not* an American Black. She is half Indian and half Jamaican.”

That user subsequently attended President Trump’s social media summit that took place at the White House last week.

Although CNN found that some of the accounts that attacked Harris during the debate were later suspended, a Twitter spokesperson said that the company had not detected any automatic bot activity. Automatic bots allow one user to send tweets across multiple accounts at once, which can have the effect of making it appear an issue or talking point is gaining traction.

Appearing on The Breakfast Club radio show on Friday, Harris was asked if she thought she was being targeted by Russian bots.

“Well, we already know we are,” she responded.

The Harris campaign provided links to a number of news articles when CNN asked what evidence it had that Russia was involved in the attacks.

Some of the stories cited respected researchers who say some of the influence campaigns they see playing out on social media bear the hallmarks of state-backed disinformation campaigns.

None of the stories, however, include confirmation from the social media companies or the US intelligence community of Russian involvement. Such confirmation has in the past taken months or years to be made public, although last November, Facebook said it had taken down a network of suspected Russian accounts just before the midterm elections, acting on a tip from the FBI.

Benjamin T. Decker, the founder of Memetica, a digital investigations consultancy, has been tracking the spread of memes attacking Harris’ racial identity. He urged caution on blaming Russia.

“In many ways, claims that ‘the Russian bots did it’ deflect from the myriad of sociopolitical problems that we face as Americans, because the majority of political disinformation is being created by and for American audiences,” he said.