Exodus of European Muslims prompts international police to act.
Europol is targeting online recruiters for the Islamic State, as it creates a police unit that will search the Internet to find those canvassing support for the group.
Starting in July, the international police force will work with unnamed social media companies to close down accounts grooming people to join the Middle Eastern insurgents, aiming to disrupt the accounts within two hours of their creation.
Rob Wainwright, director of Europol, told the BBC: "We will have to combine what we see online, with our own intelligence and that that is shared with us by European police services, so we can be a bit more targeted and identify who the key user accounts are… and concentrate on closing them down."
Islamic State sympathisers are thought to tweet 100,000 times a day from as many as 50,000 accounts, according to a study in March by the Center For Middle East Policy in the US.
The trend has caused concern in much of the West because of an exodus of Muslims to the Middle East to join rebel groups such as Islamic State, many of whom are young adults and even teenagers.
Talha Asmal, a 17-year-old from Yorkshire, is thought to be the latest such case, having allegedly killed himself in a suicide bombing in Iraq last week.
Wainwright told The Guardian that such converts came from differing circumstances, some progressing from gang life in the UK whilst others came from more privileged backgrounds.
"Who is it reaching out to young people, in particular, by social media, to get them to come, in the first place?" he asked. "It’s very difficult because of the dynamic nature of social media."
Europol’s move comes as British home secretary Theresa May prepares to advance the Extremism Bill in Parliament to tackle those that pose a "threat to the functioning of democracy".
Among those criticising the move are Christians such as Mike Ovey, who as principal of Oak Hill Theological College has argued the bill will damage freedom of speech.