The 13 people in Barcelona mowed down by a car reportedly driven by a Daesh (the self-proclaimed IS) terrorist on Thursday puts Spain on the list of countries in which vehicles have been used to ram into crowds in a series of attacks across Europe since July last year. That Spanish police killed five armed attackers in another car attack some hours later in the town of Cambrils makes the two assaults in Spain the biggest terrorist operation in one country on the continent during this period of vehicle rammings.

The Barcelona attack, which also injured over 100, was the sixth time in 13 months a vehicle has been used by terrorists to cause mass casualties in a European country, including major incidents in France, Germany, the UK and Sweden.

Since the 2004 Al-Qaeda Madrid train bombings that killed 192 people and injured around 2,000, Spain has been spared the recent slew of terrorist attacks in Europe, especially those using vehicles. The country has been until now used as a transit point by terrorists aiming for somewhere else. But Spain has now become the target.

So, once again, a driver has plowed into a crowd of innocent pedestrians, turning a car into a deadly weapon. This time, it was in the popular Barcelona area of Las Ramblas where many locals and tourists were strolling the historic streets.

Deliberately ramming a vehicle into a crowd of people is becoming a major terrorist tactic because it requires little skill to perpetrate and has the potential to cause significant casualties. While a bomb needs to be manufactured and guns smuggled, almost anybody can rent a vehicle and turn it into a land missile.

Vehicle attacks are almost impossible to prevent because not only are they readily available but there is little or no training, co-ordination or planning required. This means there are few points where individuals can be spotted by the intelligence services. It’s also very difficult to know exactly what an individual is planning to do before he or she does it. You cannot arrest someone for driving a vehicle or for having radical thoughts; in either case, it’s not a crime.

This kind of terrorism is different from the older model where members of groups would plan and train together before carrying out an attack. Due to increased surveillance by Western security agencies, terrorists have had to think up ways of working by themselves.

Europe can erect new barriers to mitigate some of the risks at key locations and there is discussion of imposing checks on those renting vans, but there are limits to what security services can do to spot and stop those planning murder in this way.

Daesh took credit for the twin Spanish attacks. A few arrests have been made but since the driver of the Barcelona tragedy has fled and the attackers in Cambrils have been killed, the authorities cannot be certain whether these terrorists entered Spain or were operating from within. The difference is crucial. Were these vehicle attacks carried out by lone wolf terrorists residing in Spain or were they launched by terrorists seeking revenge somewhere else after fleeing from Iraq and Syria where their ranks have been decimated and their territories recaptured by Baghdad and Damascus?

To the people of Spain it might not make a difference. What they know for sure is that they have joined a list of countries that have fallen victim to a growing trend. Spain and all of Europe might have to get used to vehicle attacks launched by people who for whatever reason take it into their heads to kill any number of citizens in the service of their cause.