The death of Abu Bakr al-Baghdadi, the leader of the so called Islamic State group or Daesh, leaves a vacuum at the top of the terrorist organisation, and while the frequency of IS attacks on European soil has been decreasing recently, EU officials are warning the threat is far from over.
"There might be retaliation - people who want to avenge the killing of their leader. So that's why I'm sure our security services and police are much more vigilant these days. But in the medium run, the question is, are we able to avoid the resurgence of Daesh," Gilles de Kerchove - EU Counter-terrorism Coordinator told Euronews.
The EU estimates there are still over 9,000 IS fighters in Syria and Iraq, and though their leader was killed in a US raid, many with EU passports could return home.
"There are some 500 we think European men and women who've been in detention in Syria. but there are also, we estimate, around 1,400 children with one or both parents holding EU citizenships," Julian King, EU Security Commissioner explained.
Repatriating these children has become a top priority for the EU - how EU countries should manage it regarding their radicalised parents is still not clear.
But attacks like the ones in 2015 in Paris and 2016 in Brussels were conducted by homegrown terrorists - and it wasn't until after those events that their governments greatly increased prison sentences for terrorism convictions.
"We will see in the near (next) 12 months maybe, the release of hundreds of people who were convicted and jailed five to seven years ago. And now they will go out. And most of those people didn't change their mind - so they will continue to pose a threat," explained Claude Moniquet of the European Strategic Intelligence & Security Centre.
The death of al-Baghdadi is claimed as a win in the fight against IS, but EU officials say vigilance on the streets of Europe must remain high and the battle against them in Syria and Iraq is far from over.