Hundreds of asylum-seekers entering Norway were discovered to have images of ‘executions’ and ‘severed heads’ on their mobile phones.

The revelation comes amid heightened fears that ISIS is exploiting the migrant crisis to smuggle fighters into Europe, following last month’s attacks in Paris.

Police admitted that the ‘explosion’ of refugees crossing into the country over the summer and in recent months meant that security checks were less thorough than required, and weren’t checking the background of those entering the country.

Concern: Norwegian police have admitted that the ‘explosion’ of refugees who arrived in summer meant security checks were less thorough than required. Migrants are pictured at a refugee centre in northern Norway

Horrific: Hundreds of asylum-seekers entering Norway were discovered to have images of ‘executions’ and ‘severed heads’ on their mobile phones. Pictured: A masked ISIS fighter lifts his sword above the head of a blindfolded man accused of being a sorcerer

The Police Immigration Service (PU) in Norway has been forced to work overtime and under severe pressure due to the massive numbers of asylum-seekers hoping to take refuge in the country.

But after searching belongings and mobile phones belonging to refugees and migrants crossing the border, police discovered ‘hundreds’ of examples of ‘photos and videos of executions and brutal punishments, such as images of people holding up severed heads or hands’.

They also reportedly found photographs of dead children and other victims of war, crimes and terrorism.

Numerous images of ISIS flags and symbols belonging to other terrorist organisations were also found, according to Norwegian newspaper Nettavisen.

Erik Haugland, head of Norway’s asylum programme pointed out that it was possible the images were on the phones for innocent reasons.

He explained that asylum-seekers might have the photographs in order to bear witness to the war and horrors they were fleeing in their home country, or they may have been a tactic to sneak through jihadi-controlled areas unharmed.

Forged: At least two men involved in the deadly Paris attacks may have used false Syrian passports to enter Europe, disguised as refugees

Discovery: A false passport in the name of Ahmad al-Mohammed (left) was found at the Stade de France and was registered in the Greek island of Leros. Fellow ISIS suicide bomber Bilal Hadfi (right) is also thought to have illegally returned to Europe to carry out the deadly attacks

He added that although the images may seem alarming, there are possible innocent explanations.

Meanwhile, an ISIS manifesto released earlier this month boasted of plans to exploit the migrant crisis to sneak jihadists into Europe.

It has already emerged that at least three of the group that carried out the Paris attacks in November had disguised themselves as refugees in order to enter Europe.

This includes Abdelhamid Abaaoud, who masterminded the plot and was later killed in a police raid on his hide-out in the Parisian suburb of Saint-Denis.

The forged documents were found at the scene of one of the suicide bomb attacks at the Stade de France, fuelling further speculation that ISIS may have a ready source of blank passports.

Purchase: MailOnline reporter Nick Fagge bought an identical false Syrian passport as part of an investigation into the illegal printing of Syrian identity documents

Illegal: At the time of obtaining the false documents in September, MailOnline was warned by a forger that ISIS jihadis were already using fake passports to travel outside of Syria and Iraq

American authorities announced this week that they have concerns that ISIS may have obtained a passport printing machine in an attempt to infiltrate the West using false documents.

The claim is based on a source of ‘moderate confidence’, suggesting that ISIS’s printing of passports has not been confirmed.

But MailOnline reporter Nick Fagge revealed the ease with which someone can get a Syrian passport, by buying a false Syrian passport as part of an investigation into the illegal printing of identity documents.

At the time, MailOnline was warned by a forger that ISIS jihadis were already using fake passports to travel outside of Syria and Iraq.