Legislation requiring tech companies to report on terrorist activity on their platforms is likely to be revived in the U.S., following concerns about the widespread use of Internet communications by terrorists.

A proposed rule that would require companies to report vaguely defined "terrorist activity" on their platforms had been included as section 603 in the Intelligence Authorization Act for Fiscal Year 2016.

But Senator Ron Wyden, a Democrat from Oregon, removed a hold on the bill only after the controversial provision was deleted from it.

Senator Dianne Feinstein, a Democrat from California and vice-chairman of the Senate Intelligence Committee, is now planning to introduce legislation that would make it mandatory for social media platforms like Facebook and Twitter, to alert federal officials about online terrorist activity, according to reports citing a spokesman. Feinstein's office could not be immediately reached for comment.

On Sunday, President Barack Obama said that he would urge high-tech companies to make it more difficult for terrorists to use technology to escape from justice. His address from the Oval Office came after two attackers, Syed Rizwan Farook and his wife Tashfeen Malik, killed 14 people and injured 21 others in a gun attack in San Bernardino, California.

Increasing concern about the use of social media by terrorists to communicate, coordinate attacks and win over supporters is likely to put pressure on tech companies to cooperate with law enforcement, including by pulling down content considered controversial. Obama said there were growing efforts by terrorists to poison the minds of people as the distance between countries gets erased by the Internet.

The previous section 603 would have required Internet companies that obtained "actual knowledge of any terrorist activity" to provide the relevant "facts or circumstances" of the alleged activities to the government. The provision was opposed by the tech industry and civil rights groups, because the definition of terrorist activity was too broad and could result in "overbroad reporting" with serious privacy implications for the person posting the items.