Skinny jeans
Skinny jeans have been outlawed by IS. Flickr.com

Islamic State militants have threatened to imprison any men caught wearing skinny jeans.

Its just one of a series of draconian laws outlined by the militant terror group, outlawing various forms of freedom of expression.

The introduction of the new laws were exposed by the anti-ISIS campaign group, Raqqa is Being Slaughtered Silently (RBSS), who risk their lives leaking information from inside the city.

The new sanctions include a crackdown on anyone found with music on their mobile phones; anyone caught smoking or turning up late for prayer.

Anyone who violates the laws will face ten days in prison, where they will be required to take an 'Islamic course'. At the end of their prison term, they will be forced to take a test. Those who pass will be released immediately, while those who fail the test will be fined and forced to remain in prison until they pass.

The anti-ISIS informants RBSS say the extreme interpretation of Sharia law has prompted citizens to flee the city of Raqqa.

A local resident named only as Jassem, said: "ISIS tightens penalties and uses the principle of intimidation in dealing with public, which led to the migration and escape of many people. Freedom of expression has become a crime, so you can not oppose a decision issued by the group.

"Otherwise you will be arrested on charges of violation of God's law as its fighters claim, but they are far from this law. There is no difference between ISIS and Assad's regime: bribery and favouritism are widespread within the group and play a major role, especially among the local members of the group."

Decrying western influences, earlier this month, ISIS militants carried out a mass chicken burning, condemning the consumption of produce from the US.

There was also a mass cigarette burning as the terror group stepped up its anti-smoking campaign, with members of the group's religious police force setting light to piles of cigarettes in a field.

Images also emerged earlier this week, showing dozens of black balaclava-wearing extremists graduating from an Islamic State-run school of terror in Raqqa.

Recently, a group of young men were detained by Saudi Arabian religious police for dancing at a birthday party.