Islamic State militants have ordered all men in Mosul, its Iraqi stronghold, to grow beards. The beard decree, which banned shaving, came into effect on Monday.

"What hairdressers do today, shaving and trimming men's beards, is an accessory to sin," the Islamic State said in leaflets distributed in Mosul in recent weeks, according to Agence France-Presse. "Thanks to our brothers from the Islamic police, an order has been issued for the shaving of beards to be banned and violators to be detained."

The Islamic militant outfit is going to set up "beard patrols" to oversee enforcement of the shaving ban - similar to beard patrols in Afghanistan during Taliban rule, according to Fox News. 

A Mosul resident said the Islamic State's shaving ban in Mosul has nothing to do with Islamic principles. A tougher beard policy is a ploy to make everyone a human shield in case of attacks.

"We all know what Daesh [Islamic State] is trying to achieve with these unacceptable laws on women wearing the veil and men growing beards. They want to make everyone a human shield... With military operations [to retake Mosul] looming, they want to blend in with the population," the local resident told AFP.  

"For example, ISIS members lately have been using more and more regular, unmarked civilian cars. They've ditched the military vehicles and flags. This new rule on growing beards is in the same vein. They want to hide among civilians," a Mosul-based former Iraqi security officer explained, The Express reported.

 A group of young men who refused to shave were sentenced to three months in jail in May, The Metro reported. The jihadists also warned that if these men were found breaking the new law again they would be beheaded.

Iraqi Prime Minister Haidar Al-Abadi on Monday said that security forces have launched operations to liberate Mosul, according to KUNA news agency.