James Martin/CNET

A Twitter hashtag about presidential candidate Elizabeth Warren that started trending in the US after she sparred with rival Bernie Sanders during the Democratic primary debate on Tuesday prompted some users to speculate that Russian bots could be fueling a spike in these tweets.

Twitter said Wednesday that it looked at whether bots were amplifying the #NeverWarren hashtag but found no evidence that is the case. The social network bars misleading, deceptive and spammy behavior along with attempts to manipulate what's trending.

Foreign interference in elections have been a growing concern for social media companies including Twitter and Facebook following the 2016 US presidential election. These companies discovered that Russian trolls were using their platforms to sow discord among Americans. Since then, they've been beefing up efforts to crack down on accounts that misled the public about their identity and purpose. In 2018, Twitter released more than 10 million tweets tied to potential disinformation campaigns by Russian and Iranian trolls.

At one point on Wednesday, #NeverWarren was in the top three Twitter trends in the US, The Hill reported. It started trending after Warren and Sanders disagreed during the debate about whether Sanders said during a private dinner in 2018 that he didn't believe a woman could win the presidency.

Some Twitter users started to wonder if Russian trolls and bots were amplifying this hashtag.

"I'm calling BS on the authenticity of #NeverWarren..," wrote anonymous Twitter user @NunesAlt on Wednesday. "Have we really learned nothing from 2016?"

I'm calling BS on the authenticity of #NeverWarren.



Go ahead and search it. I haven't seen any *real* prominent progressive accounts pushing it. It started taking off between 5:00 am and 7:00 am EST when all of you MFs were sleeping.



Have we really learned nothing from 2016? pic.twitter.com/VnSMvB36Qx — Devin Nunes' Alt-Mom (@NunesAlt) January 15, 2020

The Twitter user, citing Hashtags.org, pointed out that tweets with #NeverWarren started to rise at 5 a.m. EST when Americans would be asleep. At 9 a.m. EST, there were an estimated 8,100 tweets per hour with #NeverWarren, according to the site.

Other Twitter users echoed the same skepticism about why the hashtag was trending.

Most of USA is asleep right now, so when i see trending hashtags for the United States at 02:57am Mountain time,

i confess i am suspicious of their actual origin. — Hikyuu Mikado🍑🌰🍵🍂 (@Mikanojo) January 15, 2020

This is horrific.

Co-founder of @People4Bernie here. Please do NOT support this.#WarrenIsASnake #NeverWarren

It's really not helping, and is the kind of thing that Russian bots and Trump social media might be amplifying. — Yes to Big Structural Democratic Socialism (@clenchner) January 15, 2020

A hashtag starts trending on Twitter if it's being talked about more than it has previously. The list of trends is generated by an algorithm, according to Twitter. The social network, though, said that the conversations were driven by real people, including users who disagreed with its anti-Warren message. Using technology and human review, the company said it proactively tries to identify accounts that are attempting to manipulate conversations on the site.

Other news outlets, including NBC reporter Ben Collins, pointed out on Twitter that the top tweets about the hashtag were from users who denounced using it. By 3 p.m. ET on Wednesday, Twitter users tweeted #NeverWarren 62,000 times, according to NBC.

FASCINATING data here about #NeverWarren, the No. 1 trend in the United States right now.



The top three tweets about the hashtag in the world⁠—⁠from @johnpavlovitz, @mehdirhasan, @deetwocents⁠—all denounce people using it.



The algorithm is generating an opposite reality. pic.twitter.com/lAOyiS5S7G — Ben Collins (@oneunderscore__) January 15, 2020

As of late Wednesday afternoon, #NeverWarren was longer one of top five trends in the US on the Twitter. Instead, the #NeverTrump had made its way on the list.