Facebook, Google, Twitter and Microsoft have pledged to work together to crack down on terrorist propaganda online.
The four technology giants have promised to explore how they could make technical tools which spot extremist content.
The plans were announced after a meeting from senior executives at the four companies and the government’s Home Secretary Amber Rudd.
Online companies have been criticised for not doing enough to stop terror-related videos and pages spreading across the internet.
The debate flared up last week after it emerged that information on how to mount an attack was easily accessible in the wake of Westminster terrorist Khalid Masood's murderous rampage.
In a joint statement after the meeting, bosses from Facebook, Google, Twitter and Microsoft said they would "encourage the further development of technical tools to identify and remove terrorist propaganda".
Ms Rudd reported that it was a "useful discussion", and welcomed the commitment to set up a cross-industry forum.
The Home Secretary said: "My starting point is pretty straightforward. I don't think that people who want to do us harm should be able to use the internet or social media to do so. I want to make sure we are doing everything we can to stop this.
"In taking forward this work I'd like to see the industry to go further and faster in not only removing online terrorist content but stopping it going up in the first place.”
A fresh debate over authorities' access to communications was sparked after it was reported that Masood's phone connected with encrypted messaging service WhatsApp shortly before the atrocity.
WhatsApp has said it is "co-operating with law enforcement as they continue their investigations".
Masood killed four people in last week's terror attack.
Reporting by Press Association.