Before the war started, this was one of the few sites where excavations were being carried out, said Brelaud.
At the Omari Mosque, or the Great Mosque of Gaza, "we have massive destruction, with roof collapsed and part of the tower collapsing," he said.
Taha, the former minister, explained the significance of the mosque, saying it has been "a witness to almost all historical periods from the 7th century until now."
Prior to the mosque, the site had a church and, before that, a Roman temple, he said.
The Byzantine Church, also known as Jabaliya Church and dating back to the 5th century, has been completely destroyed.
Among the other sites across Gaza partially or fully damaged are the Al-Saqa Archaeological House, Tel al-Mansatar, Rafah Archaeological Tell, Deir al-Balah Museum, according to a report by the non-profit Heritage for Peace.
As Israel's military offensive shows no signs of stopping, Andreou warned that all of Gaza's historical sites "are facing an existential threat, particularly those located in densely populated areas."
"Much of the built archaeology, like mosques, churches etc. have been substantially damaged," she reiterated.