THE systematic destruction by Islamic State (IS) fighters of some of the most ancient sites in the Middle East has been denounced around the world as a further sign of the group's abhorrent mentality.

Over recent days IS has used bulldozers and other heavy equipment to damage or destroy several treasured archaeological sites in northern Iraq, including the remains of the ancient Assyrian cities of Nimrud and Khorsabad, and the 2000-year-old Hatra fortress. They had already been seen on video looting and wrecking priceless antiquities in Mosul museum.

The Patriarch of the Chaldean Catholic Church in Iraq, Archbishop Louis Sako, commenting on the destruction of Nimrud, told Vatican Radio: "This city is a very old city, before Christianity and before Islam. So IS is killing people and destroying history."

The director-general of UNESCO, Irina Bokova, said that the action by IS against Nimrud proved that "nothing is safe from the cultural cleansing under way in the country: it targets human lives, minorities, and is marked by the systematic destruction of humanity's ancient heritage."

She continued: "We cannot remain silent. The deliberate destruction of cultural heritage constitutes a war crime."

It was the duty, she said, of all political and religious leaders in the region to stand up and remind everyone that "there is absolutely no political or religious justification for the destruction of humanity's cultural heritage."

On the devastation wreaked on Hatra, Ms Bokova issued a statement jointly with the head of the Islamic Educational, Scientific and Cultural Organisation (IESCO), Abdulaziz Othman Altwaijri. This "latest act of barbarism" against a World Heritage site, the statement said, showed the contempt in which IS held "the history and heritage of Arab people".

The statement described Hatra as a large fortified city under the influence of the Parthian Empire which had withstood invasions by the Romans in AD 116 and 198, thanks to its high, thick walls, reinforced by towers. The remains of the city, "especially the temples where Hellenistic and Roman architecture blend with Eastern decorative features, attest to the greatness of its civilization".

UNESCO and ISECO said that they were ready to "assist the Iraqi people in any way possible" in coping with wholesale vandalism of ancient sites.

Although Iraqi forces, with Iranian assistance, are slowly pushing IS fighters back from territory that they seized last year, the authorities are in no position to recover what has been looted over recent months, or to apprehend the culprits. Indeed, the Iraqi authorities have suggested that the international anti-IS coalition should have been in a position to stop at least some of the destruction caused by IS.

The country's Minister of Tourism and Antiquities, Adel Fahad al-Shersab, said that Hatra was a case in point. The fortress was situated in the desert, "where it is possible to see any infiltration" from the air: "it was expected that IS would destroy it. The sky is not in the hands of the Iraqis; the sky is not in our hands."

Progress in containing and even defeating IS in Iraq does not imply that the group's regional reach is diminishing. Jihadists are operating freely in three other Arab countries where the rule of law is either weak or absent: Syria, Yemen, and Libya - the latter being the site of the recent killing of 21 Egyptian Coptic Christians.

The Prince of Wales was among those to send letters of condolences to the leader of the Coptic Orthodox Church in Egypt, Pope Tawadros II, and the General Bishop of the Coptic Orthodox Church in the UK, Bishop Angaelos.

The Archbishop of Canterbury conveyed his condolences to the Coptic Church during a visit to the Coptic Orthodox Centre in Stevenage last month.