The Senate Intelligence Committee secretly voted on June 24 in favor of legislation requiring e-mail providers and social media sites to report suspected terrorist activities.

Further Reading Islamic State takes to social media, has about 46K Twitter accounts

The legislation, approved 15-0 in a closed-door hearing, remains "classified." The relevant text is contained in the 2016 intelligence authorization, a committee aide told Ars by telephone early Monday. Its veil of secrecy would be lifted in the coming days as the package heads to the Senate floor, the aide added.

The proposal comes as the Islamic State and other terror groups have taken to the Internet to gain converts across the globe, including in the United States. The FBI issued a public warning in March about American teens being susceptible to the Islamic State's online recruitment tactics. And the Brookings Institute estimated in March that there were as many as 70,000 pro-Islamic State Twitter accounts. Twitter has removed tens of thousands of these terror propaganda accounts, which violate its terms of service.

"Our nation is facing more threats every day. America's security depends on our intelligence community’s ability to detect and thwart attacks on the homeland, our personnel and interests overseas, and our allies. This year’s legislation arms the intelligence community with the resources they need and reinforces congressional oversight of intelligence activities," Intelligence Committee Chairman Richard Burr, a Republican of North Carolina, said in a statement about the bill.

Senator Dianne Feinstein (D-CA), who sponsored the Internet services provision, did not return a call seeking comment.

The legislation is modeled after a 2008 law, the Protect Our Children Act. That measure requires Internet companies to report images of child porn, and information identifying who trades it, to the National Center for Missing and Exploited Children. That quasi-government agency then alerts either the FBI or local law enforcement about the identities of online child pornographers.

The bill, which does not demand that online companies remove content, requires Internet firms that obtain actual knowledge of any terrorist activity to "provide to the appropriate authorities the facts or circumstances of the alleged terrorist activity," wrote The Washington Post, which was able to obtain a few lines of the bill text. The terrorist activity could be a tweet, a YouTube video, an account, or a communication.

Twitter, Google, and Facebook haven't publicly taken a position on the new legislation.

Listing image by Eric Norris