The video posted online appears to show the terror group's fighters smashing artefacts in the ancient Assyrian city before blowing up the site.
Militants can be seen ripping large barrels filled with powder in a room where the walls are lined with gypsum slabs, beautifully carved with representations of Assyrian figures.
Nimrud was founded in the 13th century BC and contains one of the most famous archaeological sites in the history of a country often described as the cradle of civilisation.
It was such a special city, in fact, that it was on Unesco's tentative list of world heritage sites.
The explosion sends a huge mushroom into the sky and turns yet another important part of the region's history to dust.
The fighters hack away at statues with sledgehammers and carve them up with angle grinders, claiming that God had "honoured" them by "removing and destroying everything that was held to be equal to him and worshipped without him".
In the fake Takfirist view, statues, idols and shrines amount to recognising objects of worships other than God and must be destroyed.
A militant speaking at the end of the destruction said: "Whenever we are able in a piece of land to remove the signs of idolatry and spread monotheism, we will do it."
Nimrud is the later Arab name given to a settlement which was originally called Kalhu and was first described in 1820, being plundered by Western explorers and officials over decades.
It was also looted and damaged during the 2003 US invasion.
Most of Nimrud's most valuable artefacts were moved long ago to museums in Mosul, Baghdad, Paris, London and elsewhere but giant "lamassu" statues - winged bulls with human heads - and reliefs were still on site.
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