Following are points from a CNN article:
— European security officials estimate that 30 to 40 suspected ISIS terrorists who supported the November 13 Paris shootings that killed 130 people are still at large, and they believe they are preparing for more international attacks as the resources of security agencies are stretched beyond their limits.
— The Paris attacks that killed 130 was meant to be even broader and include other countries such as the Netherlands, and an operative allegedly linked to the Paris attackers remained free for months after authorities learned of his existence.
— The European countries most at risk are the ones launching attacks against ISIS: France, Belgium, the Netherlands, the UK, Denmark, as well as Germany.
— The US is vulnerable also due to its porous border with Mexico, and Western European passport holders can travel to the U.S. without a visa. U.S. nationals are able to travel to and from Syria and Turkey from the U.S. via Western Europe.
— It is essentially impossible to track ISIS sympathizers and former fighters due to its structure of concentric rings of secrecy where militants are unaware of who the others are that are involved. For example the people supplying the weapons used in the Paris attacks had no idea what they would be used for.
— The number of European passport holders who have traveled to Syria and Iraq range from 6,000 to 9,000 people, many of whom traveled to fight for ISIS.
— As ISIS suffers losses in Syria and Iraq, its fighters will return to Europe in record numbers to launch attacks and mobilize others. Security officials say that Europe tightening security would prompt ISIS to send as many fighters there as possible in the awareness that its ability to do so would not last indefinitely.
— During the past few years a wave of foreign fighters, a general increase in the Salafi movement, and “a sky-rocketing of right-wing-motivated criminal offenses” stretched security agencies beyond their limits. Security services in Western and Central Europe and the Balkans are operating at full capacity just by trying to identify those returning from Syria and Iraq and then trying to identify those who are a threat. Problems arise from budget and resource constraints along with sub-optimal intelligence sharing practices.
— An example of problems arising from inadequate security measures is the fact that it took months for one of the Paris attackers Abid Tabaouni to be tracked down as he was visiting Amsterdam and Brussels, with him posting pictures online of the Amsterdam’s waterfront skyline on a few occasions.
— ISIS propaganda is focusing on overwhelmingly inciting “lone wolf” individuals to launch independent attacks such as the Orlando nightclub shootings, which is a difficult element for security services to contend with.