video has emerged of isis thugs sledgehammers and ak-47 rifles to destroy walls and statues in iraq 's unesco world heritage city of hatra .
in the slickly produced seven minute footage , jihadists are shown smashing shrines and statues in the 2,000-year old city .
militants are also recorded chipping away at the bases of some of the larger wall sculptures and cracking boulders into ancient city pillars , while eerie music plays in the background .