Hundreds of asylum seekers entering Norway have been discovered with images of “Isis flags” and “executions” on their mobile phones, Norwegian police have said.

The Police Immigration (PU) in Norway have reportedly been working under severe strain to register increasing numbers of refugees hoping to seek asylum in the country.

Police told the Norwegian newspaper Nettavisen “hundreds” of examples of “photos and videos of executions and brutal punishments, such as images of people holding up severed heads or hands” have been found after searching the luggage and phones of new arrivals.

Authorities also discovered numerous examples of Isis flags and symbols belonging to other terrorist organisations, according to reports.

The discoveries come amid concerns Isis may be utilising the refugee crisis in order to smuggle extremists into Europe, following the string of terror attacks in Paris last month, which killed 130 people.

Last month the French Prime Minister, Manuel Valls, announced some of the Paris attackers “took advantage of the refugee crisis” to slip into Europe.

Mr Valls was among a number of leaders calling for tighter security at the Schengen area’s external borders after Greek authorities confirmed one of the suicide bombers at the Stade de France used a fake Syrian passport to enter the EU as an asylum seeker.

Reports of concerning images being found in the possession of refugees' surfaced earlier this year.

A director of the Norwegian government asylum division told Norwegian newspaper Dagsavisen in March: “It can be very demanding to find out who these people are and what they have done.

“We have to detect whether they have taken part in terrorist operations, deserted a terrorist operation or defected from a terrorist organization, and that’s critical for our evaluation of their application”.

Hanne Jendal at the Immigration Directorate said asylum seekers found to have participated in criminal acts would be denied refugee status, The Local reports.

Since 2008, between 90 and 100 people have been denied asylum due to past participation in terrorism.

The number of asylum seekers making first-time applications in Norway has been steadily rising throughout this year, Eurostat figures show.

In January the number stood at just 570 but in October, the most recent month recorded, the total hit 8,575.

The Norwegian government is paying asylum seekers to return to their home countries as the refugee crisis continues.

The immigration department’s return unit (UDI) figures show more than 900 people have applied to take financial support to leave Norway so far.