A Nazi-hunting group urged Twitter and other social media Wednesday to step up efforts to remove online "hate speech," citing a surge in incitement to attacks like the recent Boston bombings.
The Simon Wiesenthal Center said Twitter has spawned nearly 20,000 hash tags and handles this year that are linked to terrorism and extremism, up 30 percent in the past year.
"If we want to make it tougher for the terrorists to recruit, we need (actions by) Facebook, Google, Twitter and YouTube," said Abraham Cooper, associate dean of the Wiesenthal Center, at a Capitol Hill briefing.
"The proliferation of terrorism tutorials, and the abuse of social media and online forums by extremists, portend that future 'lone wolf' attacks here and abroad are inevitable."
Cooper said that Facebook has been far more active in "scrubbing" pages which appear to incite hate and violence, and has been open to feedback from his group, But he said Twitter has refused to even discuss the matter.
"We have been unsuccessful in even getting an answer from Twitter" about its efforts, Cooper said.
"The bad guys know how to use Facebook and Twitter," he said, to recruit and promote violence.
The organization gave Facebook a rating of A-minus for taking "tremendous steps to identify and eliminate digital prejudice and hate on their site."
It gave YouTube a grade of C-minus, saying the Google-owned video site allows many tutorials used by attackers to remain online.
Twitter was given a grade of F by the center, which said "You can post anything you want without being screened or removed."
Twitter did not respond to an AFP request for comment. The messaging platform's terms of service state that Twitter is not responsible for content posted, but that users "may not publish or post direct, specific threats of violence against others."
The center, which was founded in 1977 by Nazi hunter Wiesenthal, a Holocaust survivor, published the data in its 15th annual report on digital hate and terrorism.
Explore further: Google to help boost Greece's tourism industry