Internet giants will face increased pressure to tackle online extremism as European leaders were expected to back a UK-led drive for tougher internet regulation.
Foreign Secretary Boris Johnson will lead calls to ensure there is "no safe space for terrorists" to plot attacks and share radical material online when he attends a meeting of EU foreign ministers in Luxembourg on Monday.
In the wake of atrocities in London Bridge and Manchester, Prime Minister Theresa May has urged social media companies such as Google, Facebook and Twitter to take down terrorist content, agreeing measures with G7 leaders in April and a new plan with French President Emmanuel Macron last week.
Mr Johnson will also encourage the bloc's 28 foreign ministers to join forces to track foreign fighters returning from Iraq and Syria.
Speaking ahead of the meeting, Mr Johnson said: "We are pushing back Daesh militarily, but the threat we face is evolving rather than disappearing as they lose ground in Iraq and Syria.
"The fight is moving from the battlefield to the internet.
"There should be absolutely no safe space for terrorists plotting attacks, radicalising young people and encouraging others to carry out violence in the name of an obscene ideology.
"We all want to protect our people so we must say together that enough is enough. Terrorism affects us all and we need a common approach to ensure the problem gets solved, and at a much faster pace than we are seeing right now."