Swedish Islamists have reacted with joy at the Paris attacks, writing praise from their new homes in the Islamic State and promising more of the same.

One ‘Swedish’ Muslim propagandist who publishes pictures of himself wielding automatic weapons glorifying jihad and calling on other people in Sweden to join the Islamic State praised the Paris terrorists. Posting online, he wrote the killings were “this beautiful revenge… it is in the name of Allah”, reports Sweden’s high-circulation left-wing daily Afton Bladet.

Another jihadist who previously lived in Sweden is a 25-year-old man, who warned the West and Russia against retaliatory attacks after the Paris killings. Posting to Facebook he said: “If Hollande bombs Muslims in Syria we will bomb his civilians. If Putin kills our women and children, we will bring war to his streets.

“You are conducting a war against Syria and Iraq to kill our civilians. By Allah, we will shoot your civilians wherever you are”.

Before he travelled to Syria, the young man promising to kill civilians in France and Russia was active in his local Muslim ‘congregation’ in Sweden and was in charge of youth activities at his mosque. The Swedish security service are aware of the postings and are investigating.

Extremism is a serious and growing problem in Sweden, with the number of Islamist radicals lying low in the country without any interference from the government leading one senior police officer this weekend to call the nation a “sleeper country” for Islamism.

An estimated 300 ‘Swedes’ have travelled to wage jihad for Islamist groups including the Islamic State, and one small Swedish city has the highest recruitment rate for Muslim terror of any in Europe. Of the 300 that have travelled to fight, an estimated 100 have since returned to Sweden, but not a single one has been prosecuted for their actions abroad.

This lax attitude towards security has made Sweden, like Belgium, a hub for radical Islam in Europe, as without proper control the ideology is allowed to flourish .