As France is left reeling from several shootings in the space of 24 hours, risk analysts and terrorism experts fear that cash-strapped Europe is ill-equipped to deal with the threat.
"All the advances that have been made in counter-terrorism in Western countries over the last few years have been primarily intelligence-led rather than harsh policing responses, however, the difficulty is resources," David Lea, Western European Analyst at Control Risks, told CNBC Europe's "Squawk Box" on Thursday.
"Intelligence assets are a finite resource and countries are struggling with that. We hardly need remind people of the budgetary pressures that European countries are under at the moment and this is just another one."
Despite the risk posed by militant groups like Islamic State, Boko Haram, Al-Qaeda and Al-Shabaab, cash-strapped governments across the region have chosen to either not increase their defense and counter-terrorism efforts as part of cost-cutting and austerity measures.
Last year, the European Union's Counter-Terrorism Coordinator, Gilles De Kerchove, warned the U.K. government's Home Affairs Select Committee on counter-terrorism capacity that national budgets devoted to counter-terrorism were declining across the EU but "that the threat that we face is becoming more diverse, more diffuse, and more unpredictable."
In addition, he called for "concerted and co-ordinated action" by European countries to "avoid destabilization … and the establishment of terrorist safe havens."
Thursday's attack highlighted the importance of maintaining -- if not, increasing -- spending on counter-terrorism in Europe, another analyst told CNBC.
"Events like yesterday highlight the importance of counter-terrorism measures and intelligence gathering as being the core of security in societies within Europe," Alan Mendoza, executive director of London-based Henry Jackson Society think-tank.
"It's up to politicians to decide whether they think that's important enough to put the necessary resources in. We've seen defense cuts in this sort of area because of budgetary restraints and I think it's time to recognize that we need to up the ante on this," he added.
Mendoza said he could not put a figure on how much more needed to be spent on counter-terrorism measures but he believed that not enough investment was being made in intelligence gathering to prevent attacks.
"We have probably not invested enough in terms of our ability to intercept communications like this – it is controversial too as people don't like being snooped on but a balance needs to be struck between security and liberty."
Not all analysts are convinced that throwing money at the problem can help prevent the threat of terrorism.
Haras Rafiq, managing director of the counter-terrorism think tank Quilliam Foundation, told CNBC that there had to be two responses to counter-terrorism.
"We have to have the harsh end of preventing these kind of attacks -- that is the interventions, the arrests, the hard criminal security response to these individuals but the long-term battle will only be won if we promote the ideals that we believe in in a liberal, western society, that has to be the long-term strategy."
Rafiq says that European hopes of integrating their ethnic communities with education were a "red-herring" and that society had to make an effort to target the underlying ideology of Islamic extremism.
"Integration is a red herring and education has nothing to do with it, these are red herrings – 49 percent of the British convicted terrorists have had higher education -- the real strategies are around combating the Islamist ideas but also promoting the things that we believe in...We need to take this battle of ideas right to the forefront of society."