Civil liberties and human rights are key pillars of the European Union (EU) but after yet another terrorist attack in a European capital, questions are being asked over whether the bloc needs to restrict freedoms amid the heightened terrorist threat.
Terrorist attacks in Brussels left at least 31 people dead, according to the latest figures, and hundreds injured. The terrorist group that calls itself Islamic State (IS) claimed responsibility for the bombings that took place Tuesday in the capital city's airport and a metro station.
Belgian public broadcaster RTBF said on Wednesday morning that the airport suicide bombers were brothers Khalid and Ibrahim el-Bakraoui and were known to the police. A manhunt is now underway for a third suspect, named by media reports as 24 year old Najim Laachraoui.
Read MoreFor the latest on the Brussels attacks, click here.
Police states
The Belgian attacks come after more than a decade of Islamist-inspired suicide bombings, bomb attacks and shootings in Madrid, London, Paris, Copenhagen, Frankfurt and Toulouse. As a result, questions are being asked over the strength of Europe's defenses against radicalization, terrorist networks and the apparent ease of movement of suspects throughout the continent.
Freedom of movement and travel within the continent is viewed as a basic freedom for European citizens - and there could be widespread protests if they were rolled back. Likewise, a right to privacy and freedom from surveillance is cherished too and there has been resistance to any moves to allow intelligence agencies more access to private communications.
Speaking to CNBC on Wednesday, the Belgian Ambassador to the U.K. Guy Trouveroy said there was a danger of losing freedoms in the so-called "global war on terror."
"Let's see how the balance will be made there. But I would say that in Belgium at least it is up to our Prime Minister, our politicians, to present options (over how to tackle terrorism) but I would say that to transform our countries into police states, I am not sure that would be the right response. Also because if (we do that) then we start antagonizing communities again," he said.
"You have to realize that it's not always to protect every single place where human beings assemble and do you want to change your society to such an extent that you make your life much more difficult," he said. "By doing so, you're handing over a fantastic victory to these terrorists."
Security checks
The Belgian authorities have come under criticism for not sharing more intelligence within the country's police and intelligence departments and for also not doing enough to address the lack of integration of the country's Muslim community.
Although he accepted that there was too much division between rival police and intelligence authorities in Belgium, Mark Demesmaeker, a Belgian politician and member of the European parliament, told CNBC that a global approach to terrorism and information-sharing was needed.
"What we need is better cooperation, maximum cooperation between European national intelligence and security services. We have to unite against this menace. (These attacks) can happen all over Europe. Next time it might be Amsterdam or Berlin or London again. This kind of terrorist org is working at a global level so we need to address this at a global level."
Signaling that information-sharing was not as easy as it sounded, Matthew Henman, managing director of IHS Jane's Terrorism and Insurgency Centre (JTIC) told CNBC that the scale of information sharing needed was huge.
"It's questionable really even if you have proper intelligence-sharing measures in place whether they're still significant resources to adequately analyse, understand and track all the potential threats across Europe, it's almost a Herculean task."
- By CNBC's Holly Ellyatt, follow her on Twitter @HollyEllyatt. Follow CNBC International on Twitter and Facebook.