Twitter has publicly touted its efforts to suspend accounts linked to ISIS, but according to a new study, white nationalists and neo-Nazis continue to use the social network "with relative impunity." The study, published last week by George Washington University's Program on Extremism, found that major white nationalist groups have seen a surge in Twitter followers since 2012, while ISIS has seen its influence decline on the social network. The findings were first reported by Reuters.

The report analyzed 18 Twitter accounts operated by prominent white nationalist groups and leaders, with followers mostly based in the US. The analysis found that self-identified Nazi sympathizers and white nationalists had "substantially higher follower counts than ISIS supporters, and tweeted more often." The median follower count for Nazi-linked accounts was nearly eight times higher than ISIS-affiliated handles, and their average count was more than 22 times greater.

"On Twitter, ISIS’s preferred social platform, American white nationalist movements have seen their followers grow by more than 600% since 2012," reads the study, which was authored by J.M. Berger. "Today, they outperform ISIS in nearly every social metric, from follower counts to tweets per day."

Last month, Twitter announced that 360,000 accounts have been suspended for promoting terrorism since mid-2015, including 235,000 suspensions since February. Authorities in Europe and the US have called on Facebook, Twitter, and other major tech companies to crack down on ISIS propaganda and online recruitment, raising concerns that their efforts may infringe on free speech. Germany, in particular, has pressured social networks to more swiftly remove xenophobic content and other hate speech directed toward refugees. But Berger's report says that policing white nationalist and Nazi content is more challenging, because the communities are "less cohesive than ISIS networks, and less concentrated on Twitter."

"While the extreme violence of ISIS has understandably elevated concerns about the threat the organization presents, other extremist groups are able to watch its success and learn from its tactics, both on social media and offline," the report says. "Studies of ISIS activity, while useful, examine only a fraction of the violent extremist landscape."

"White nationalist users referenced Trump more than almost any other topic"

When reached for comment by Reuters, a Twitter spokesman cited the company's terms of service, which prohibit users from posting content that promotes terrorism or targets other users based on race or ethnicity. Twitter's ongoing struggle to police abuse on its platform gained renewed attention in July, after Ghostbusters actress Leslie Jones published a spate of racist messages she received on the site. In August, the company expanded features that allow users to filter any threats and abuse they receive, and it is reportedly developing a feature that would allow them to block certain keywords.

Donald Trump's presidential campaign also appears to have shaped the way white nationalists use Twitter, according to the study published last week. In April 2016, three of the 10 most popular hashtags used by white nationalist groups referred explicitly to Trump's campaign: #trump, #trump2016, and #makeamericagreatagain. The Republican candidate has faced criticism for repeatedly retweeting posts from users linked to white nationalist movements.

"White nationalist users referenced Trump more than almost any other topic, and Trump-related hashtags outperformed every white nationalist hashtag except for #whitegenocide within the sets of users examined," the report says.