Europe-wide police agency Europol is to set up a new security team in order to detect and block the social media accounts of ISIS.
According to a study conducted in the US, more than 46,000 Twitter accounts have been used by ISIS militants.
Washington’s Brooking Institution claimed that the number of ISIS-linked accounts could be up to 90,000.
Europol's director Rob Wainwright said that the new security team is to start work at the beginning of July.
"Who is it reaching out to young people, in particular, by social media, to get them to come, in the first place? It’s very difficult because of the dynamic nature of social media," Wainwright said.
"We will have to combine what we see online, with our own intelligence and 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."
Europol’s new team is to work together with a variety of social media companies to detect ISIS-linked accounts, and will aim to find and close every opened account within a two-hour time.
According to an International Center for the Study of Radicalization (ICSR) report, more than 20,000 foreign fighters joined the ranks of ISIS in Syria and Iraq by the time the report was released in late 2014, nearly one-fifth of them residents or nationals of Western European countries.
The report covers 14 European countries and says the number of foreign fighters from Western Europe has exceeded almost 4,000, double the number in December 2013.
France, the United Kingdom and Germany have produced the largest number of foreign fighters, while Belgium, Denmark and Sweden are the countries with the highest number of militants relative to their populations, the ICSR report says.
The ICSR data shows France leading the way with an estimated 1,200 fighters, followed by the the UK and Germany with 500-600 fighters and the Netherlands with 200-250 fighters.
The total number of people fighting with ISIS is 20,730 worldwide, which makes it the largest mobilisation of foreign militants since World War II, surpassing the Afghanistan conflict of the 1980s.
The report estimates that around 5-10 percent of the foreign fighters have been killed during clashes, while another 10-30 percent have left the conflict zone, mostly returning to their home countries or becoming stuck in transit countries.