Robin Wainwright, the British director of the European Union’s law enforcement agency, made the comments during a panel discussion with NATO Secretary General Jens Stoltenberg at World Economic Forum Annual Meeting in Davos on Friday.
And he said the agency was only able to carry out its work thanks to help from the USA while NATO said they are expecting a positive relationship with the new Trump administration depite fears the new President would withdraw support.
Mr Wainwright made his comments at a NATO summit in Davos
Addressing the conference alongside EU foreign policy chief Federica Mogherini, Mr Wainwright called on the EU to implement a ban on the movement of terrorists between members states.
He said: "We have to manage freedom of movement, which we cherish in Europe but at the same time, there’s an expectation from our public that we don’t allow terrorists to move freely between our countries.
"We have to perennially manage the balance between privacy and security and indeed a very important point.
US NATO troops have recently arrived in Poland for new training exercises
"You know, the space between the shared responsibility between national governments and those operating at the EU level, very clear what the Lisbon Treaty says, of course, that national security of which terrorism is a form shall be the sole responsibility of member states, that’s what the treaty says very clear.
"However, the nature of the terrorist threat facing Europe today is by its very nature a trans-national one and of course requires at least an element, a significant element of trans-national cooperation.
"Institutions like Europol have been upgraded to respond to the data sharing challenge especially and by helping to identify more quickly and more proactively the terrorist actors involved."
NATO Secretary General Stoltenberg said US relations are a priority
The conference, attended by politicians, security, defence chiefs and business leaders also touched upon the US elections and controversy surrounding comments President Donald Trump has made about NATO.
Mr Wainwright also added that the US has been responsible for helping Europol to tackle cyber crime after it was revealed at the conference that there are at least 50,000 criminals being investigated.
He added: "It’s because of the Americans that we have a leading edge now, I think, in many of the cyber-crime investigations that we’re doing and increasing engagement on terrorism as well.
The free movement of people has caused major security issues
"So, I think actually, Europol is a modern success story of transatlantic security cooperation and I’m pretty sure my American counterparts would be saying exactly the same thing."
Secretary General Stoltenberg also insisted that the US relationship is a top priority.
He said: "It is so important that international institutions adapt because in times of turmoil and uncertainty, we need strong international institutions.
NATO training exercises
Wed, June 8, 2016
The North Atlantic Treaty Organization, also called the North Atlantic Alliance, is an intergovernmental military alliance based on the North Atlantic Treaty
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Polish troops land with parachutes at the military compound near Torun, central Poland as part of the NATO Anaconda-16 military exercise
"The UN, the EU, NATO, the World Bank, IMF, all these institutions that were created after the Second World War, they are children of turmoil over a war and we need to continue to use these international institutions to preserve peace and stability.
"For NATO, that means that we need to adapt to a new security environment and that’s exactly what we are doing.
"One key element in that is to make sure that we have a strong transatlantic bond also in this new security environment and just to be clear about that because everyone asks me about that, I’m absolutely confident that also with a new US administration, we will have a strong US commitment to a strong transatlantic partnership in NATO".