Iraq's government is investigating reports that the ancient archaeological site of Khorsabad in northern Iraq is the latest to be attacked by the ISIS militant group.

Adel Shirshab, the country's tourism and antiquities minister, told AP there are concerns the militants will remove artefacts and damage the site, located 9 miles northeast of Mosul.

Saeed Mamuzini, a Kurdish official from Mosul, told AP that the militants had already begun demolishing the Khorsabad site on Sunday, citing multiple witnesses.

On Friday, the group razed 3,000-year old Nimrud and on Saturday, they bulldozed 2,000-year old Hatra – both UNESCO world heritage sites.

UN Secretary General Ban Ki Moon has called the destruction a "war crime," and a "outraged by the continuing destruction of cultural heritage in Iraq".

Khorsabad was constructed as a new capital of Assyria by King Sargon II shortly after he came to power in 721 BC and abandoned after his death in 705 BC.

It features a 80-feet thick wall with a stone foundation and seven gates.

Since it was a single-era capital, few objects linked to Sargon II himself were found. However, the site is renowned for shedding light on Assyrian art and architecture.

The sculptured stone slabs that once lined the palace walls are now displayed in museums in Baghdad, Paris, London and Chicago.

Isil currently controls about a third of Iraq and Syria. The Sunni extremist group has been campaigning to purge ancient relics they say promote idolatry that violates their fundamentalist interpretation of Islamic law.

A video released last week shows them smashing artefacts in the Mosul museum and in January, the group burned hundreds of books from the Mosul library and Mosul University, including many rare manuscripts.