BRUSSELS - Even as Europe powered up its most ambitious ever cybersecurity exercise this month, doubts were being raised over whether the continent's patchwork of online police was right for the job.
The exercise, called Cyber Europe 2014, is the largest and most complex ever enacted, involving 200 organisations and 400 cybersecurity professionals from both the European Union and beyond.
Yet some critics argued that herding together normally secretive national security agencies and demanding that they spend the rest of 2014 sharing information amounted to wishful thinking.
Others questioned whether the law enforcement agencies taking part in the drill should be involved in safeguarding online security, in the wake of American whistleblower Edward Snowden's revelations of online spying by western governments.
"The main concern is national governments' reluctance to cooperate," said Professor Bart Preneel, an information security expert from the Catholic University of Leuven, in Belgium.
"You can carry out all of the exercises you want, but cybersecurity really comes down to your ability to monitor, and for that, national agencies need to speak to each other all the time," Preneel said.
The Crete-based office coordinating the EU's cybersecurity, the European Union Agency for Network and Information Security (ENISA), calls itself a "body of expertise" and cannot force national agencies to share information.
As with most aspects of policing and national security, the EU's 28 members have traditionally been reluctant to hand over powers to a central organisation, even when - as in the case of online attacks - national borders are almost irrelevant.