A Nazi-hunting group has urged Twitter and other social media 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 hashtags 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," the center's associate dean Abraham Cooper said 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" to recruit and promote violence, he added.
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.
"You can post anything you want without being screened or removed," the center said about the micro-bloging center.
A Twitter spokesman said in a statement sent to AFP that the company does not "mediate content or intervene in disputes between users."
"However, targeted abuse or harassment may constitute a violation of the Twitter rules and terms of service," the spokesman added.
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 and Holocaust survivor Wiesenthal, published the data in its 15th annual report on digital hate and terrorism.