European security officials fear that Islamic State is seeking to weaponise migrants who have already entered Europe.

Europol, the European Union (EU) police agency, had reported it was “indisputable” that jihadists entered the EU posing as migrants during the migrant crisis. Now, security agencies believe Islamic State may be radicalising and recruiting migrants who have already successfully crossed the continent’s borders and passed through vetting processes, reports Voice of America.

“We have to be ready,” said Fabrice Leggeri, executive director of Frontex, the EU border and coast guard agency, prior to the Berlin Christmas market attack.

“Some people might get radicalized or manipulated or used or utilized by terrorist groups after they enter the EU,” he said. “This is something where I don’t have clear indications.”

A report released in December by Europol’s European Counter Terrorism Centre (ECTC), “Changes in Modus Operandi of IS Revisited”, states, “A real and imminent danger is the possibility of elements of the (Sunni Muslim) Syrian refugee diaspora becoming vulnerable to radicalisation once in Europe and being specifically targeted by Islamic extremist recruiters.”

The report continued, “It is believed that a number of jihadists are travelling through Europe for this purpose. According to unconfirmed information, German authorities were aware of around 300 recorded attempts made by jihadists to recruit refugees who were trying to enter Europe by April 2016.”

“ISIS just wants to give itself options,” said Robin Simcox, a terrorism and national security analyst with the Heritage Foundation.

“It chimes perfectly with what ISIS would want to do,” he added. “It enables them to extend their foreign operations.”

Anis Amri, who drove a truck through the Berlin Christmas market on Monday 19 December killing 12 and injuring over 50, was described by his father as a violent, drug-taking troublemaker in his youth in Tunisia – but not religious.

It was not until he had travelled illegally to Europe following the Arab Spring in March 2011 that he was reportedly radicalised in an Italian jail, before travelling on to Germany where he presented himself as a Syrian and applied for asylum. Amri was shot dead by Italian police after pulling a weapon on and shooting an officer on the morning of Friday the 23rd of December.

Through its Amaq news service, Islamic State released a martyrdom video of Amri swearing allegiance to the caliphate and leader Abu Bakr al-Baghdadi.

Jenan Moussa, a reporter for Al Aan TV, based out of Dubai, United Arab Emirates, provided a translation of what Amri said in the video, describing it as evidence that he “isn’t a lone wolf after all – at least he was in touch with ISIS media.”

Amri said in the recording, “I call my brothers everywhere, make Jihad in the name of God and support this religion’s [duty] … If you are in Europe fight these crusade[r] pigs.”