Bearded as well as clean-shaven members of the eight-man unit are pictured posing with long-range Russian-made Dragunov sniper rifles in northern Iraq. 

Adopting the look of an American sniper unit, the fighters are kitted out in khaki uniforms, peaked caps and ski goggles to protect them from the glare of the sun. 

According to the US-based jihadi tracking organisation, Site, the unit is part of the Ninewa Division of northern Iraq. It is one of 16 administrative regions in the Islamic State that spans Syria and Iraq.

ISIS snipers have seen action in both Syria and Iraq where they have been responsible for the deaths of many Kurdish and Iraqi soldiers.

An ISIS sniper killed Iranian Revolutionary Guard Brigadier General Hamid Taqavi in December. Taqavi was one of a number of Iranian advisers training Shi'a militias in their fight against ISIS. 

They have also played a prominent role in the battle for Kobane which involved intense street fighting.

ISIS Twitter accounts were quick to link the battalion to a famous Iraqi sniper who plagued American forces during the Iraqi conflict. 

One said the unit was carrying on the legacy of 'Juba the Sniper', a Sunni insurgent sniper who operated in Baghdad from 2005 where he is said to have killed around 40 American soldiers.

The film American Sniper is directed by Clint Eastwood and based on Chris Kyle's autobiography American Sniper: The Autobiography of the Most Lethal Sniper in US Military History. 

With 255 kills, 160 of which were officially confirmed by the Department of Defense, Kyle is the deadliest marksman in US military history. 

But the film, which stars Bradley Cooper and Sienna Miller, includes a character named Mustafa, shown as a rival to Bradley Cooper's portrayal of Chris Kyle, undoubtedly based on Juba.

A shadowy figure, Juba claimed to be a soldier in the Sunni insurgent Islamic Army in Iraq (IAI) - which included former members of Saddam Hussein's Ba'ath Party, his intelligence services and officers of the Republican Guard. 

(dailymail.co.uk)