Militant group ISIL has released new video showing their destruction of the ancient Assyrian city of Nimrud in northern Iraq.

The city, once one of the best-preserved examples of one of the Middle East's most ancient civilisations, was targeted for destruction by ISIL earlier this year.

The new video shows fighters taking hammers to artifacts and well-preserved frescoes, before apparently leveling the city itself in a huge explosion.

ISIL have released pictures and video of them destroying ancient historical artifacts and sites. (Supplied) (Supplied)

ISIL claimed the city embodied "un-Islamic" attitudes. (Supplied) (Supplied)

ISIL claimed the ancient depictions and carvings of old gods in the city were idolatrous and un-Islamic.

The city was one of the oldest remaining sites from the Assyrian civilisation. (Supplied) (Supplied)