In a further crackdown on the Islamic State group’s extensive propaganda campaign, a new Europe-wide police unit is being formed to block all ISIS-linked web accounts and hunt down extremists behind the practice. Led by the European police agency Europol, the unit will start its work from July 1, and is expected to take down pro-ISIS social media accounts within two hours of detection, the Guardian reported Sunday.

The new Europol web unit will seek to hunt down the key figures associated with the estimated 100,000 tweets a day posted through 45,000 to 50,000 accounts linked to ISIS. The tweets are shared as part of the terrorist group’s social media propaganda campaign to recruit foreign fighters across the world. Rob Wainwright, Europol's director, told the Guardian that police would work with social media companies to track pro-ISIS accounts, while the major goal of the unit would be to “identify the ringleaders online.”

“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 told the Guardian, adding that Europol would not name the social media companies that have agreed to cooperate with the authorities.

According to Wainwright, about 5,000 Europeans, including people from the U.K., France, Belgium and the Netherlands, have traveled to ISIS-controlled territories to join the jihad.

A recent study by the Brookings Institution, a Washington-based think tank, found that from September through December 2014, at least 46,000 Twitter accounts were used by ISIS supporters. The study also found that pro-ISIS accounts had an average of about 1,000 followers each, which is considerably higher than those of an ordinary Twitter user.

Aaron Zelin, an expert on jihadist groups, told BBC that ISIS uses Twitter to draw the attention of potential new recruits, but not to directly hire them. According to him, the group uses other platforms such as Skype, WhatsApp and Kik for more direct conversations with its sympathizers.

In October, FBI revealed that three American teenage girls left Colorado to join ISIS in the Middle East. The girls were later back home after the FBI found them in Frankfurt, Germany, on their way to Syria. According to the Search for International Terrorist Entities Intelligence Group (SITE), the teenage girls followed online jihadists from around the world and used to spend extensive time on social media sites like Instagram, Twitter and Facebook.

In February, three teenage girls from the U.K. left their homes to join ISIS in Syria. It later emerged that one of the girls had used Twitter to contact the wife of an ISIS fighter before leaving the country.

“It [ISIS] may be medieval in its outlook, but it is modern in its tactics, with the internet as the main tool to spread its warped worldview,” Bloomberg quoted British Prime Minister David Cameron as saying last week. “The nature of the threat is grave.”