French president Francois Hollande has issued a call to preserve the cultural heritage threatened by the Islamic State group in Iraq and Syria, after extremists have demolished relics and pillaged archaeological sites in both countries.

Hollande symbolically made a speech Wednesday in a room of the Louvre museum in Paris exhibiting major artifacts of the Assyrian palace of Khorsabad in northern Iraq -- an ancient site that was attacked by IS earlier this month.

Extremists also razed 3,000-year-old Nimrud and bulldozed 2,000-year-old Hatra in Iraq, events described by UNESCO as "cultural cleansing."

Hollande said experts from the Louvre will "soon" go to Baghdad in order to evaluate the resources needed to preserve the antiquities.

He said French subsequent excavation discoveries in the region will be scanned and made available to Iraqi authorities. Some Iraqi doctoral students will be invited to complete their studies in France.

"We must do everything we can to preserve the treasures" of Iraq and Syria, said Hollande, standing amid the antiquities of the Louvre -- the first museum to exhibit treasures of the Assyrian civilization in the 19th century.

UNESCO will document the sites that have been attacked, train historians and archeologists, and fight against the trafficking of objects obtained through illegal excavations, French ambassador to UNESCO Philippe Lalliot said.

"We need to get an accurate knowledge of what has been destroyed or looted" in order to be able to trace the items and flag them to custom services, Interpol, and auction houses, Lalliot said.

A UN resolution adopted on February 12 bans all trade with antiquities illegally removed from conflict zones in Iraq and Syria.

UNESCO has classified six Syrian sites --including the ancient cities of Aleppo and Damascus-- and two Iraqi sites in its list of world heritage in danger.

Islamic State extremists last year captured Iraq' northern city of Mosul and its surroundings, a region where nearly 1,800 of Iraq's 12,000 registered archaeological sites are located.