French Prime Minister Manuel Valls said the mastermind of Paris attacks and some more terror spreading people managed to enter Europe unhindered by exploiting the refugee crisis.

The 27-year-old Abdelhamid Abaaoud was wanted on international warrants and in his absence a Belgium court sentenced him twenty years in prison. Police thought him to be in Syria, but he managed moving freely in EU.

The mastermind was also linked to several of extremist plots this year in France.

On Wednesday he was killed in a police raid in northern Paris suburb of Saint Denis that triggered a massive firefight and explosions. He was hiding in an apartment building. A tip-off from Moroccan intelligence helped the Belgian police track down Abaaoud.

The French prime minister has urged to introduce a passenger name record system that will collect the data of people entering European Union. He added the external borders must be strengthened too of EU.