ISIS has torn down an ancient structure known as the 'Gate of God' in its ongoing destruction of religious, cultural and archaeological icons in the Middle East.

The Mashqi Gate dates back to the 7th century BC, and was one of several entry points to the ancient biblical city of Nineveh, Iraq – once considered to be one of the most important cities in the Assyrian empire.

Activists in Mosul, which has been under ISIS control since June 2014 and parts of which are built on Nineveh's ruins, told ARA News that military equipment was used to tear down the gate.

ISIS has declared ancient relics to be idolatrous, and has destroyed many religious sites in Iraq and Syria.

The group has specifically targeted Christian sites, and experts claim militants have looted and sold on millions of pounds worth of artefacts from ancient churches across Iraq and Syria to fund their regime.

Early last year, jihadists looted and bulldozed the ancient Assyrian city of Nimrud in northern Iraq, and released video footage of militants destroying ancient artefacts in the Mosul Museum, which housed thousands of ancient Assyrian artefacts, many of them from Nineveh.

A source at the British Institute for the Study of Iraq confirmed to the Independent that the 'Gate of God' had been attacked by militants.

The source also cited unconfirmed reports that stone blocks from the Walls of Nineveh were being sold off by jhadists.