WASHINGTON (Reuters) - Senior White House officials and U.S. intelligence and law enforcement figures will meet with Silicon Valley executives on Friday to discuss how to counter the use of social media by militant groups, sources familiar with the meeting said on Thursday.

The White House Chief of Staff Denis McDonough attends a ceremony to light the U.S. National Chanukah (Hanukkah) Menorah on the Ellipse in Washington, December 6, 2015. REUTERS/Sait Serkan Gurbuz

In an escalation of pressure on technology firms to do more to combat online propaganda from groups such as Islamic State, the meeting follows attacks in Paris and San Bernardino, California, that underscored the role played by social media companies such as Twitter Inc TWTR.N, Alphabet Inc's GOOGL.O YouTube and Facebook Inc FB.O.

Invited participants include White House Chief of Staff Denis McDonough, presidential counter terrorism adviser Lisa Monaco, Attorney General Loretta Lynch, FBI Director James Comey, National Intelligence Director James Clapper and National Security Agency Director Mike Rogers, one of the sources said.

A source familiar with the meeting said it would focus on social media content, not encrypted communications, another topic of discussion between Silicon Valley and the White House.

Twitter, Apple Inc AAPL.O, Facebook and Google are attending, the companies said. Several other Internet firms, including Microsoft Corp MSFT.O and Dropbox, are expected to attend, according to those familiar with the meeting. Most companies are expected to send high-ranking executives, but not their chief executive officers.

An administration announcement is expected following the conclusion of the summit, according to a source.

Twitter last week updated its policies for policing its content to explicitly prohibit “hateful conduct.” Other websites have similarly updated and clarified their abuse policies within the past 18 months.

The meeting agenda covers how to make it harder for militants to recruit and mobilize followers on social media, as well as helping ordinary users create, publish and amplify content that can undercut groups like Islamic State.

The meeting also will touch on how technology can be used to disrupt paths to violent radicalization and identify recruitment patterns, and how to make it easier for law enforcement and intelligence agencies to identify militant operatives.

The Obama administration “has been clear about the importance of government and industry working together to confront terrorism, but we do not have any specific meetings to announce or preview at this time,” a senior official said.

Amid rising public concern about the potential for more attacks, President Barack Obama in a speech in December said, “I will urge high-tech and law enforcement leaders to make it harder for terrorists to use technology to escape from justice.”

Tech firms have been increasingly cooperative, taking down content viewed as capable of inciting violence or recruiting militants. But those same firms are often reluctant to appear too cozy with government investigators, a concern that grew after Edward Snowden disclosed wide government surveillance.