Two schools in Sweden have come under fire from school inspectorate authorities after it was revealed that migrant-background children being taught lessons in their native language were actually just learning the Quran.

The issue was raised through an anonymous tip to the school inspectorate which exposed that the Quran, and other elements of the Islamic faith such as prayers, were being used in so-called mother-tongue education, Swedish broadcaster SVT reports.

Mother-tongue education is used for the children of recently arrived migrants to help them learn and keep up with their fellow classmates while they are learning Swedish.

The head of one of the schools in the municipality of Vingåker involved in the accusations said: “If it occurs then it must immediately cease. It is completely unacceptable,” and added that no religious content was acceptable, according to the school’s rules.

“We do not give room for prayer or special studies of the Quran. If it occurs, it must be stopped immediately,” the school director added.

The number of children eligible for receiving part of their education in their mother tongue has increased dramatically in Sweden over the last ten years to around 270,000, according to a report from last December.

Sweden Tumbles In International Schools Performance League, Mass Migration Blamed https://t.co/jBzlNpcUYy pic.twitter.com/uXurPU5x5Z — Breitbart London (@BreitbartLondon) March 15, 2016

Some politicians, such as Moderate Party member Camilla Brunsberg, have called for banning mother-tongue education entirely, arguing that the programme takes up too many resources for municipal governments and that declining test results were related to areas with mother-tongue education in place.

Schools in the most heavily migrant-populated areas of the country have seen issues, particularly ones in troubled no-go zone suburbs like Rinkeby in Stockholm.

A report from the Swedish National Agency for Education released in March claimed that half of the students in grade nine at schools in Rinkeby were underperforming and were not even qualified enough to enter high school.

A similar report from the Swedish Expert Group on Public Finance (ESO) in 2017 claimed that migrant children coming to Sweden after the age of seven had a 50 per cent chance of passing into high school, compared to a 70 per cent pass rate in 1998.