"You will never prevent someone leaving his apartment, taking a knife in the kitchen and killing someone in the street, I'm sorry," Gilles de Kerchove has told DW. 

In an exclusive interview on Conflict Zone, the EU's counter-terrorism chief told DW's Michel Friedman that individuals posing a threat had to be identified earlier to prevent attacks: "That's the work which has been undertaken for years on training better community police officers, using more and more sophisticated software to spot weak signals. So, when is it that someone gets radicalized and reaches the tipping point where he will use violence?"

According to figures released in June by Europol, the European Union's law enforcement agency, there were 142 deaths and 379 people injured in the EU in 2016 from terrorist attacks. Of the deaths, 135 came from 13 jihadist attacks.

"I have to accept the harsh criticism that we should have avoided that, so we need to fix it and even improve further," said de Kerchove.

'Nothing like' 100 percent security

Asked whether the EU has a better answer to the terror threat in Europe, the EU’s anti-terror chief said: "I acknowledge that we need to improve but I wouldn't draw the conclusion that Europe hasn't done anything. […] Many attacks have been prevented. Many plots have been foiled. But of course some have succeeded. There is very sadly nothing like 100 percent security but we have improved a lot."

A survey published by the European Parliament in April 2016 showed that 69 percent of respondents "consider EU action [on fighting terrorism] to be insufficient" and 82 percent want it to "take more action".

"We are investing a lot," said de Kerchove.

"The President of the Commission launched the idea of a security union. […] He appointed a full-time Commissioner, Julian King, who is monitoring the implementation of the security union and we have developed a lot of new policies, adopted a lot of legislation, supported a lot of effort in the member states to collect passenger name record information to cross the data."

Data collection concerns

Passed in the European Parliament in April 2016, the Passenger Name Record (PNR) directive will give EU countries access to data already stored by airlines, such as travel dates, contact details and payment information.

Initially proposed in 2011, negotiations were stalled by debate over privacy concerns.

"Eventually we managed to reach a consensus. […] The institution is keen to strike the balance right between privacy and security and we don't want to rush to become a 'Big Brother' society. And therefore that takes time," said de Kerchove.

EU member states must implement the legislation by May 2018.

'Virtual caliphate'

Asked what was being done to tackle what de Kerchove has previously referred to as a "virtual caliphate" that could outlast Islamic State, he told DW: "We have been very active. The commission set up a public-private partnership with the big internet companies at the request of the member states […] We have removed 90 percent of what has been flagged to the companies. And we put a lot of pressure on them so that they developed algorithm to detect in an automated way the unlawful content."