"The average rate of returnees to Western countries is now at around 20-30%, presenting a significant challenge to security and law enforcement agencies that must assess the threat they pose," the report stated.
"Estimates indicate that more than 5,000 fighters from member states of the European Union alone have made the trip to Syria," it added, highlighting that France and Belgium "top the poll for the highest number of fighters per capita."
The report revealed that there was a well-organized network of about "90 kamikazes-in-waiting" in the EU.
In his recent Op-Ed for The Washington Post, American journalist and author David Ignatius asks why the Belgian security service failed to prevent the latest attacks, while European and American intelligence agencies are believed to be keeping an eye on terrorists travelling in and out of the Syrian war zone.
"Belgium's failure was cooked into the system: The jihadists move stealthily, and the Belgians didn't collect or share enough of the intelligence that was there. Authorities had allowed Molenbeek to become a haven — more dangerous to Belgium than even the jihadists' sanctuaries in Syria, Iraq and Libya," Ignatius stresses.
However, he notes, if Americans believe that the tragic event is none of their concern, they are completely wrong.
"The Islamic State's [Daesh's] rampage is more an American failure than a European one," he emphasizes.
"The failure of the US-led coalition to contain the jihadists has left a fragile Europe exposed to terrorism and social upheaval," Ignatius points out.
A series of color revolutions in the Middle East and North Africa, backed by the West, have turned the regions into a hornet's nest. As a result, the unrest reached the shores of Europe.
"The policies are those the Western powers have followed in the Middle East for decades. The first is the failure to promote a viable solution to the long running Israeli-Palestinian conflict. The second is the disastrous policy of regime change Western governments have pursued in the Middle East since 2000. The third is the West's habit of manipulating local jihadi terrorists in order to achieve its geopolitical goals," Alexander Mercouris, a London-based expert on international affairs, wrote in his recent Op-Ed for Sputnik.
To mend the problem, "European intelligence services must combine forces with the United States and with each other," Ignatius believes.
As of yet the "shockingly dysfunctional" European security system has not been improved.
"Schengen agreements should have been suspended completely after the equally foul atrocity in Paris," former MP George Galloway told Russia Today in the wake of the Brussels tragedy.
However, such a stance signals that the very idea of the existence of the unified Europe is now threatened.
"If Europe were a stock, a pragmatic investor would sell it, despite the sunk cost and sentimental attachment. Without radical restructuring, it's an enterprise headed for failure," Ignatius underscores.