Analysis by defence analysts IHS shows that the area under the terror group’s control has shrunk by 28 per cent since its peak in January 2015 as counter insurgents and air strikes push the terrorists back.
In the first nine months of this year, ISIS lost a chunk of territory roughly the size of Sri Lanka as the total area under their control fell from 30,115 sq miles to 25,290 sq miles.
But the rate of territory loss appears to have slowed after Russia begins scaling back the number of air strikes against ISIS targets.
In the three months to October ISIS has lost just 1,080 sq miles.
Alex Kokcharov, principal Russia analyst at IHS told the BBC: "Last September, President Putin said it was Russia's mission to fight international terrorism and specifically ISIS, Independent reported.
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