Islamic State has destroyed a monastery in Iraq that was the oldest in the country and one of the oldest in the world.

Satellite photographs obtained by the Associated Press show the 1,400-year-old St Elijah's monastery near Mosul has been completely obliterated.

AP used satellite imagery firm DigitalGlobe to take photos of the site and compared them with earlier images.

According to imagery analyst Stephen Wood, the destruction took place between August 27 and September 28, 2014.

"Bulldozers, heavy equipment, sledgehammers, possibly explosives turned those stone walls into this field of gray-white dust. They destroyed it completely," Wood said. "There's nothing to rebuild."

The monastery was a place of pilgrimage for Iraqi Christians and was used for worship by US troops based nearby.

AP quotes an Iraqi priest based in Irbil, Rev Paul Thabit Habib, aged 39. When shown the pictures he said: "I can't describe my sadness. Our Christian history in Mosul is being barbarically leveled. We see it as an attempt to expel us from Iraq, eliminating and finishing our existence in this land."

Mosul was the heartland of Christianity in Iraq before its Christian population was driven out in 2014. Many churches have been destroyed along with paintings and statues. It was reported last October that several churches were used for slaughtering animals during Bakr-Eid, the Islamic Festival of Sacrifice.

The monastery, called Dair Mar Elia, is named for the Assyrian Christian monk who built it between 582 and 590 AD. It was the scene of a massacre in 1743 when 150 monks were killed on the orders of a Persian general; now the last witness to their deaths has been obliterated.