ONCE again Europe has been wracked by terrorist attacks. Over the last few days three acts of bloodshed have occurred. In Berlin a lorry ploughed into a popular marketplace, killing 12 people, while in the Turkish capital, Ankara, the Russian ambassador was gunned down,as were three men in an Islamic Centre in Zurich.

In the past 13 months, Europe has become a crucible of terrorist activity. According to counterterrorism officials, if there is any solace to be gleaned in this grim scenario, it is that the European security services upped their game following the deadly Paris attacks of November last year. This may well be so, but the fact remains that Europe is only as strong as its weakest security system or database when faced with such a transnational threat.

Islamic State (IS), al-Qaeda or other organisations don’t make any distinction between countries in or out of Schengen or the EU. For precisely that reason most experts admit there is still much to be done in strengthening existing EU agencies.

The latest attack in Berlin is precisely the kind of strike IS has been urging its followers to carry out. The killing of the Russian ambassador in Turkey, on the other hand, illustrates another side of the complex labyrinth of terrorism, territorial dispute, rebellion and sectarianism that is consuming the Middle East and spreading its consequences into Europe.

Both incidents give some idea of the vast range and multi-layered set of challenges counterterrorism agencies face. In particular the nexus between IS and Europe grows closer. For some time now – since the start of the current military operation to retake the Iraqi city of Mosul that serves as the de facto capital for IS – there have been fears that the jihadists will shift tactics, concentrating on attacking Europe rather than holding the dwindling territory of their self-proclaimed caliphate. While there is no way of telling at this stage whether the attack in Berlin is the first sign of this, counterterrorism officials are bracing themselves for a substantial rise in the threat level emanating from Syria and Iraq.

The enormous flow of people escaping these conflicts from the Middle East to Europe only adds to their problems. While it goes without saying that most refugees are law-abiding people who are fleeing violence, extremism and terrorism, IS has clearly exploited and infiltrated their numbers. At the same time, this vast, uprooted population provides plenty of alienated and disconnected people, some of whom can be recruited by pro-terror propaganda.

Given all of this, the European Commission should be supported in its proposals to squeeze the space in which terrorists can operate. Cutting off terrorist sources of funding and weapons supplies, while at the same time tackling online propaganda and radicalisation, are all crucial in this strategy.

Above all else though, the root source of the problem, the conflicts in the Middle East, need to be resolved. It is from these open wounds that the germ of terrorism primarily emanates. Curing these ills, of course, poses an altogether different kind of political challenge.